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Resumen Introduccion:  - lactamasas de espectro extendido (BLEE) son enzimas plasmidiales que confi eren resis-tencia a multiples antimicrobianos. Las bacteriemias por enterobacterias productoras de BLEE restringen las opciones terapeuticas y aumentan la mortalidad. Objeti-vo : Realizar una descripcion clinica y molecular de las bacteriemias causadas por enterobacterias productoras de BLEE. Metodo : Se estudiaron retrospectivamente los casos de bacteriemia por Escherichia coli , Klebsiella pneumoniae y Proteus spp. confi rmadas para BLEE, en adultos ingresados en un hospital universitario durante los anos 2004-2007. Se revisaron los registros clinicos y de susceptibilidad. Se realizo tipifi cacion molecular por reaccion de polimerasa en cadena y estudio de clonalidad por electroforesis de campo pulsado. Resultados: Se iden-tifi co una prevalencia de BLEE de 9,8% en enterobacterias causantes de bacteriemias. Se observo susceptibilidad disminuida a quinolonas y aminoglucosidos, sin resisten-cia a carbapenemicos. Los tipos de BLEE predominantes fueron CTX-M (96%), TEM (62%) y GES (28%). El 79% de las cepas presento mas de un tipo de BLEE. El analisis clinico revelo alta frecuencia de patologias de riesgo, uso previo de antimicrobianos y uso de dispositivos invasores. No se encontro clonalidad signifi cativa.

Objetivos: Establecer la etiologia de la neumonia y comparar el rendimiento de diferentes tecnicas para el diagnostico de las infecciones por Pneumocystis jiroveci y Mycobacterium tuberculosis en pacientes con infeccion por virus de inmunodeficiencia humana (VIH). Material y Metodos: De cada paciente se obtuvo esputo inducido y se efectuo LBA. A las muestras obtenidas se les realizo tinciones de Gram, Ziehl-Neelsen, plata e inmunofluores-cencia (IF) para P. jiroveci y M. tuberculosis; reaccion de polimerasa en cadena (RPC) para ambos microorganismos; cultivos aerobicos, fungicos, para micobacterias, virus respiratorios y citomegalovirus. Tambien se realizo determinacion de IgM de Mycoplasma pneumoniae y Chlamydophyla pneumoniae y antigeno urinario de Legionella pneumophila. Resultados: Se incluyeron 60 pacientes, lograndose diagnostico etiologico en 97% de los casos. Pneumocystis jiroveci fue la etiologia mas frecuente (58%), seguida por Streptococcus pneumoniae (12%) y Mycobacterium avium complex (MAC) (12%). Mycobacterium tuberculosis fue encontrado en 5%. Conclusiones: La comparacion de los metodos diagnosticos para P. jiroveci mostro una mayor sensibilidad de la IF y tincion de plata en LBA que en esputo; sin embargo, la RPC fue igualmente sensible en ambos tipos de muestras. Con esta estrategia se logro establecer etiologia en la gran mayoria de los pacientes. La etiologia mas comun fue P. jiroveci. IF en LBA sigue siendo el estandar para el diagnostico de la neumonia por P. jiroveci.

Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality.To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria.We retrospectively studied the cases of bacteremia due to ESBL-producing Escherichia coli, Klebsiella pneumoniae and Proteus spp in adults admitted to a university hospital during the years 2004-2007. We reviewed the clinical records and antimicrobial susceptibility patterns. Molecular typing was performed by polymerase chain reaction and study of clonality by pulsed-field electrophoresis.We found a prevalence of 9.8% ESBL in enterobacteria causing bacteremia. Decreased susceptibility to quinolones and aminoglycosides was observed, without resistance to carbapenems. The predominant ESBL types were CTX-M (96%), TEM (62%) and GES (28%). 79% of the strains presented more than one type of ESBL. Clinical analysis revealed high prevalence of risk factors, previous use of antimicrobials and of invasive devices. There was no significant clonality.The presence of ESBLs in bloodstream infections is a clinical problem that must be considered when choosing empiric therapy.

Introduccion: Streptococcus agalactiae es el principal agente causal de sepsis perinatal precoz. La adquisicion de politicas de prevencion ha traido consigo la utilizacion frecuente de antimicrobianos intra-parto. La vigilancia de resistencia antimicrobiana se hace indispensable para definir el farmaco de eleccion y alternativas en dicha profilaxis. Nuestro centro realiza tamizaje universal desde hace 10 anos. Objetivos: Determinar la evolucion de la resistencia antimicrobiana de S. agalactiae de colonizacion materna, a los antimicrobianos utilizados en la prevencion de sepsis neonatal, entre 2002 y 2008. Metodos: Se estudiaron 100 muestras vaginales-anales positivas para S. agalactiae de mujeres embarazadas, con edad gestacional de 35 a 37 semanas. Se realizo estudio de susceptibilidad in vitro por discos a penicilina, ampicilina, cefazolina, eritromicina y clindamicina, segun metodo estandarizado por Clinical and Laboratory Standards Institute (CLSI). Resultados: Se analiza la susceptibilidad de 99 cepas. Diecisiete fueron resistentes a eritromicina (17,1%) y 13 eran resistentes a clindamicina (13,1%). De las 17 cepas resistentes a eritromicina, 13 eran fenotipo MLS y 4 del fenotipo M. Dentro del fenotipo MLS, la resistencia fue constitutiva en nueve cepas e inducible en cuatro cepas (test D positivo). En comparacion con el ano 2002, hubo un aumento significativo de resistencia a clindamicina (de 3,2 a 13,1% p < 0,002) y a eritromicina (de 1,09 a 17% p < 0,001). Streptococcus agalactiae se mantuvo 100% sensible a penicilina y ampicilina. Conclusiones: S. agalactiae mantiene alta sensibilidad a los antimicrobianos de eleccion para la prevencion de sepsis neonatal y a un antimicrobiano alternativo: cefazolina. Se observo un aumento significativo de resistencia antimicrobiana a clindamicina y eritromicina. Se hace necesario, entonces, solicitar antibiograma en el tamizaje del tercer trimestre del embarazo, en pacientes alergicas a penicilina.

Toxoplasmosis (T) is a major chronic parasitic infection in immunocompromised patients and pregnant women. It is important to discriminate between acute phase (AT) and chronic phase (CT). Diagnosis is serological in immunocompetent patients (concentration of IgG and IgM).To evaluate the utility of an IgG avidity test (A-IgG) to identify the acute and chronic stage. Avidity is the strength of affinity between a specific immunoglobulin and the protein antigenic epitope of the infecting agent, an affinity that increases over time.We used a qualitative kit that measures the avidity of IgG, discriminating the two phases. In 35 patients with clinical diagnosis of AT and/or CT, IgG, IgM and IgG A (VIDAS®) were performed.Patients with AT were positive for IgM and IgG, but presented weak avidity. In the 21 cases with CT, 52% (n: 11) were IgM positive and 100% (n: 21) had positive IgG with strong avidity.The results confirm that the test of A-IgG may be useful in the diagnosis of AT, and has 100% concordance with reference test (qualitative IgM + quantitative IgG). The result is available within 24 hrs, and may be useful in diagnosis of AT in pregnant women.

Globalization of health care seems to be irreversible and beyond cultural differences and local realities; consequently, medical education needs to have a common set of core principles or standards that may be applied worldwide. The aim of participating in assessment processes is to guarantee that medical education takes place in a sufficiently rich environment to promote extensive academic purposes. The Medical School of the Pontificia Universidad Católica de Chile (PUC) participated in three assessment processes that included three stages: internal assessment, external assessment, and accreditation judgment. Two of these assessments were voluntarily carried out following the standards set by the Liaison Committee on Medical Education-LCME, and they took place in 1997 and 2007. The other assessment was based on standards set by the Chilean accrediting organism, the National Committee for Undergraduate Program Accreditation (Comité Nacional de Acreditación de Pregrado-CNAP) and took place in the year 2001. In all three experiences, internal assessment was the most enriching stage, stimulating refections among students and teachers in order to recognize areas of strengths and weaknesses. External assessment processes, especially those based on international standards, are very important for the institutional and program development of Medical Schools. The PUC Medical School on its whole learnt how to carry out an assessment process and was able to improve several weaknesses without pressure, moving from quality assurance to quality enhancement. The present paper analyzes the major challenges involved in an external assessment process.

Introducción: Toxoplasmosis (T) es una infección parasitaria crónica importante en pacientes inmunocompro-metidos y mujeres embarazadas. Es relevante discriminar entre fase aguda (TA) y fase crónica (TC). Su diagnóstico es serológico en inmunocompetentes (detección de IgG e IgM). Objetivo: Evaluar la utilidad del test de avidez IgG (A-IgG) para identificar la fase aguda y o crónica. Avidez es la fuerza de afinidad entre una inmunoglobulina específica y el epítope de la proteína antigénica del agente infectante, afinidad que aumenta con el tiempo. Pacientes y Métodos: Se usó un test cualitativo que mide la avidez de IgG, discriminando las dos fases. A 35 pacientes con diagnóstico clínico de TA y o TC, se les realizó IgG, IgM e A-IgG en Equipo VIDAS®. Resultados: Los pacientes con TA fueron positivos para IgM e IgG y presentaron avidez débil. Los 21 casos con TC 52% (n: 11) tuvieron IgM positivo y 100% (n: 21) tuvo IgG positiva con avidez fuerte. Discusión: Los resultados confirman que el test de A-IgG puede ser de gran utilidad en el diagnóstico de TA, concordancia: 100 % con test de referencia (IgM cualitativa + IgG cuantitativa). El resultado está disponible en menos de 24 hrs, pudiendo ser útil en el diagnóstico de TA en mujeres embarazadas. Introduction: Toxoplasmosis (T) is a major chronic parasitic infection in immunocompromised patients and pregnant women. It is important to discriminate between acute phase (AT) and chronic phase (CT). Diagnosis is serological in immunocompetent patients (concentration of IgG and IgM). Objective: To evaluate the utility of an IgG avidity test (A-IgG) to identify the acute and chronic stage. Avidity is the strength of affinity between a specific immunoglobulin and the protein antigenic epitope of the infecting agent, an affinity that increases over time. Patients and Methods: We used a qualitative kit that measures the avidity of IgG, discriminating the two phases. In 35 patients with clinical diagnosis of AT and/or CT, IgG, IgM and IgG A (VIDAS®) were performed. Results: Patients with AT were positive for IgM and IgG, but presented weak avidity. In the 21 cases with CT, 52% (n: 11) were IgM positive and 100% (n: 21) had positive IgG with strong avidity. Discussion: The results confirm that the test of A-IgG may be useful in the diagnosis of AT, and has 100% concordance with reference test (qualitative IgM + quantitative IgG). The result is available within 24 hrs, and may be useful in diagnosis of AT in pregnant women.

Globalization of health care seems to be irreversible and beyond cultural differences and local realities; consequently, medical education needs to have a common set of core principles or standards that may be applied worldwide. The aim of participating in assessment processes is to guarantee that medical education takes place in a sufficiently rich environment to promote extensive academic purposes. The Medical School of the Pontificia Universidad Catolica de Chile (PUC) participated in three assessment processes that included three stages: internal assessment, external assessment, and accreditation judgment. Two of these assessments were voluntarily carried out following the standards set by the Liaison Committee on Medical Education-LCME, and they took place in 1997 and 2007. The other assessment was based on standards set by the Chilean accrediting organism, the National Committee for Undergraduate Program Accreditation (Comite Nacional de Acreditacion de Pregrado-CNAP) and took place in the year 2001. In all three experiences, internal assessment was the most enriching stage, stimulating refections among students and teachers in order to recognize areas of strengths and weaknesses. External assessment processes, especially those based on international standards, are very important for the institutional and program development of Medical Schools. The PUC Medical School on its whole learnt how to carry out an assessment process and was able to improve several weaknesses without pressure, moving from quality assurance to quality enhancement. The present paper analyzes the major challenges involved in an external assessment process.

Introduccion: No existe consenso en cuanto a que se considera flora nasal normal. Recientemente, ha emergido Staphylococcus aureus meticilino resistente comunitario (MRSA-com) en personas sin factores de riesgo conocido, produciendo una alarma sanitaria a nivel mundial. Objetivo: Determinar la colonizacion nasal bacteriana y evaluar la presencia de MRSA-com. Material y metodo: Estudio prospectivo descriptivo, entre octubre de 2007 y octubre de 2008, en poblacion sana. Se realizo toma de muestra de secrecion nasal, incubacion e identificacion bacteriana por metodos convencionales. Resultados: Poblacion estudiada con promedio de edad 37,6±15,8 anos, 55% de sexo femenino, y 37,1% tabaquismo activo. Se obtuvo 73%> de cultivos positivos. Se identificaron 18 especies bacterianas, siendo las mas frecuentes Staphylococcus coagulasa negativo (53%) y Staphylococcus aureus (22,7%). Se detecto solo un caso de MRSA, cuyo analisis genetico fue negativo para demostrar su origen comunitario. Discusion: Existe una alta tasa de portacion nasal de S coagulasa negativo y S aureus, similar a lo reportado por la literatura internacional. Pese a que la prevalencia encontrada para S aureus es la habitual, no se encontraron muestras positivas a MRSA-com. Lo anterior indica que aun no existe en Chile la diseminacion de clones de MRSA-com.

Introduccion: Los metodos comerciales de reaccion de polimerasa en cadena (RPC) estan validados para el diagnostico de Mycobacterium tuberculosis solo en muestras respiratorias con baciloscopia positiva. En muestras con baciloscopia negativa, la sensibilidad es variable. Objetivo: Evaluar el comportamiento de la RPC en uso en muestras con baciloscopia negativa. Metodo: Se compararon los resultados de 235 muestras analizadas por cultivo en agar Loewenstein-Jensen ("estandar de oro") y RPC (AMPLICOR MTB test®, Roche). Resultados: Se analizaron 181 muestras respiratorias y 54 muestras extra-respiratorias. La sensibilidad de la RPC fue de 88 y 50%), respectivamente, la especificidad y el VPP fueron, en ambos casos, de 100%o, y el VPN fue de 99,4%o en muestras respiratorias y de 96,1%) en extra-respiratorias. Conclusiones: El buen desempeno de esta RPC en muestras respiratorias con baciloscopia negativa permite al medico clinico tomar decisiones en base al resultado de este examen, fundamentadamente. En muestras extra-respiratorias, solo pueden sacarse conclusiones frente a resultados de RPC positivos.

Campylobacter jejuni es un agente habitual de enterocolitis en humanos. La campilobacteriosis ha sido catalogada como una zoonosis cuyo reservorio es la microbiota intestinal de las aves de corral. El tratamiento con antimicrobianos sólo está recomendado a los casos graves y/o prolongados. Con el fin de evaluar la susceptibilidad in vitro de Campylobacter jejuni, dado la aparición de resistencia a los fármacos utilizados habitualmente en el tratamiento de la diarrea aguda, se realizó este estudio en 73 cepas aisladas de coprocultivo. Los antimicrobianos evaluados fueron: eritromicina, azitromicina, ampicilina y ciprofloxacina. De las 73 cepas evaluadas por epsilometría, 32,4% de las cepas fue resistente a ciprofloxacina y 6,4% presentó susceptibilidad dismunuida a ampicilina. No se detectó resistencia a eritromicina ni azitromicina. Es importante realizar la vigilancia de resistencia antimicrobiana en C. jejuni para conocer su patrón de susceptibilidad y evaluar aquellos antimicrobianos utilizados empíricamente en el tratamiento de la enterocolitis bacteriana.

The use of techniques for the detection of nucleic acids such as the polymerase chain reaction (PCR) has had a major impact on microbiological analysis, playing an important role in the clinical laboratory. Most of the techniques currently used are designed for specific detection of a particular microorganism. However, infectious agents can also be identified even if genus or species are unknown, using universal primers to amplify bacterial or fungal DNA and then identify the species by sequence (universal or wide spectrum PCR). This methodology is applied in cultures that are difficult to identify using phenotypic techniques, and more recently it is also being used directly in clinical samples, where the detection and identification of the infectious agent by traditional techniques is difficult or not possible.

The objective of this multicenter study was to determine tigecycline susceptibility rates, measured by agar diffusion, in nine hospitals in Santiago and to compare these rates with other antimicrobials. Each center studied 20 strains per month. All intermediate and fully resistant strains as well as 10% of susceptibile strains were also studied by the broth microdilution method. Overall, 2301 strains were studied displaying the following susceptibility rates for tigecycline: 100% for Streptococcus sp, Enterococcus sp, and E. coli respectively, 99.8% for Staphylococcus sp, 93% for Klebsiella and 80% for Acinetobacter baumarmii. For Proteus, Providencia and Morganella the susceptibility rates were 4%. For cefotaxime-resistant Klebsiella and imipenem-resistant A. baumarmii susceptibility rates were 95% and 80% respectively. The agar diffusion and broth dilution method were 100% concordant for tigecycline susceptible strains but only 27% for resistant or intermediate strains represented mostly by Acinetobacter baumannii. The majority of these strains (57/59) proved to be susceptible after retesting. The great majority (96,6%) of strains tested from nine Chilean hospitals proved to be susceptible to tigecycline with exception for Proteus, Providencia and Morganella (66% resistance). Using the agar diffusion method for measuring tigecycline susceptibility to A. baumannii may be misleading.

The surveillance of febrile neutropenia (FN) episodes in every center allows adapt the antibiotic therapy guidelines to local epidemiology.To characterize clinical features and compare the FN etiology between hematological cancer (HC) and solid organ cancer (SOC) in our center.Surveillance study in adult patients with FN admitted to Hospital Clinico Universidad Católica, in Santiago, Chile, from January 2004 to August 2007.154 FN episodes corresponding to 87 patients were included. Mean age: 47 +/- 6 years-old; 71% had HC and 29% SOC. A clinical and/or microbiologically documented infection was recognized in 76%. Gastrointestinal 31.5%, upper respiratory 30.3% and lower respiratory 16.9% were the more frequent clinical focus. In 30.5% blood culture resulted positive: gram negative rods 51%, gram positive cocci 41% and yeasts 8%; being Escherichia coli 22%, S. coagulase negative (SCoN) 20% and Klebsiella pneumoniae 12% most frequent bacteria; 22.2% Enterobacteriaceae were ESBL producers and 55.6% 5CoN were methicillin resistant. In 18.3% of FN episodes the etiology was not established. Highest mortality was observed in episodes with microbiologically documented infection (14.5% vs 1.3%, p0.005). A clinical observed focus and positive blood cultures were more frequently obtamed among HC than SOC associated episodes: 37.3% vs 13.6%; (p0.01) and 67.2% vs 50%; (p = 0.045), respectively.The etiological profile of FN in our center and the necessity to continue the surveillance was described. Future studies are needed regarding risk factors of invasive infection that have worst prognosis.

Para conocer la susceptibilidad a tigeciclina por difusión en agar en nueve hospitales de Santiago y comparar la susceptibilidad con otros antimicrobianos, se diseñó este estudio multicéntrico. Cada centro estudió 20 cepas mensualmente. Las intermedias, resistentes y 10%o de las susceptibles se re-testearon y estudiaron por microdilución en caldo. Se incluyeron 2.304 cepas. Fueron susceptibles a tigeciclina Strep-tococcus sp (100%o), Enterococcus sp (100%), E. coli (100%o), Staphylococcus sp (99,8%), Klebsiella pneumoniae (93%) y Acinetobacter baumannii (80%). En Proteus, Providencia y Morganella la susceptibilidad fue 4%o. Klebsiella resistente a cefotaxima y Acinetobacter resistente a imipenem, 95%o y 80%o fueron susceptibles a tigeciclina, respectivamente. La concordancia en cepas susceptibles y en las enviadas como resistentes o intermedias (A. baumannii) fue 100%o y 27%o respectivamente. El re-testeo confirmó que la mayoría eran susceptibles. Los patrones de susceptibilidad bacteriana muestran muy buena actividad in vitro a tigeciclina. La resistencia in vitro de A. baumannii por difusión en agar debe interpretarse con precaución.

Introduccion: La vigilancia de la etiologia de los episodios de neutropenia febril (NF) en cada centro permite adaptar guias de antibioterapia a la epidemiologia local. Objetivo: Caracterizar y comparar la etiologia de la NF en pacientes con cancer hematologico (CH) y de organos solidos (COS). Pacientes y Metodos: Estudio de vigilancia de NF de pacientes adultos en el Hospital Clinico Universidad Catolica, en Santiago, Chile, entre enero 2004 y agosto 2007. Resultados: 154 episodios de NF correspondientes a 87 pacientes: 47 ± 6 anos; 71% CH y 29% COS. Se documento infeccion clinica y/o microbiologicamente en 76%o. Mas frecuente fueron: foco gastrointestinal 31,5%, respiratorio alto 30,3%o y respiratorio bajo 16,9%o. En 30,5%o hubo hemocultivos positivos: bacilos gramne-gativos en 51%, cocaceas grampositivas en 41%, levaduras en 8%o; predominando: Escherichia coli 22%o, Staphylococcus coagulasa negativa (SCoN) 20%o y Klebsiella pneumoniae 12%; 22,2%o de las entero-bacterias eran productoras de (3-lactamasa de espectro expandido y 55,6%o >SCoN meticilina resistentes. En 18,3%o de los episodios no se identifico causa de fiebre. Hubo mayor mortalidad en episodios con documentacion microbiologica (14,5% vs 1,3%, p < 0,005). En los pacientes con CH fue mas frecuente obtener hemocultivos positivos (37,3%o vs 13,6%; p < 0,01) e identificar foco clinico (67,2% vs 50%; p = 0,045). Conclusiones: Se establece el perfil etiologico de las NF en nuestro centro y la necesidad de mantener vigilancia. En futuros estudios sera necesario evaluar factores de riesgo de pacientes con infecciones invasores que tendrian peor pronostico.

Mycetoma is a chronic infection that affects skin, subcutaneous tissue and bone. Its etiology can be mycotic or bacterial. It affects mainly the lower extremities of middle age men living in tropical climates. We report a 44-year-old male living in a template zone, consulting for swelling and pain in the left foot, lasting for 10 years. Physical examination showed a swollen left foot with hyperpigmented skin and a few crusted papules. Radiology showed an extensive bone involvement of the midfoot with several oval and radiolucid images. Magnetic resonance showed soft and bone tissue involvement, with multiple oval and low intensity images in T1 and T2. The biopsy was compatible with an unspecific chronic osteomyelitis. A bacterial identiFcation by polymerase chain reaction and sequencing in the biopsy determined the presence of an Actinomadumra madurae. Treatment with cotrimaxazol was started.

Listeria monocytogenes is Gram-positive facultative intracellular pathogen often foodborne and found elsewhere. It is an uncommon cause of illness in the general population. However, it is an important cause of severe infection in neonates, pregnant women, elderly and immunosuppressed patients. Listeriosis has unique preference for pregnant women. Maternal listeriosis is a diagnostic challenge, and intrauterine infection can lead to severe complications such as amnionitis, preterm labor, spontaneous abortion, stillbirth and neonatal sepsis. From 2001 to 2005, 16 patients with L. monocytogenes were identified in this hospital; four (25%) were pregnant women. Clinical and laboratory findings are described. There were 3 preterm deliveries and 1 spontaneous second trimester abortion. Three women with listeriosis had no predisposing factors other than pregnancy. One patient was on immunosupressive drugs for ulcerative colitis. Fever was the most common symptom. Infected neonates were most commonly diagnosed with early-onset listeriosis (two cases) or fetal demise (one case). Pregnancy can be the only risk factor for listeriosis. Listeriosis should be considered during the evaluation of febrile syndrome in pregnancy as this condition can be the only risk factor. Blood and amniotic fluid cultures are useful diagnostic tests. Perinatal complications remains high.

Listeria monocytogenes is Gram-positive facultative intracellular pathogen often foodborne and found elsewhere. It is an uncommon cause of illness in the general population. However, it is an important cause of severe infection in neonates, pregnant women, elderly and immunosuppressed patients. Listeriosis has unique preference for pregnant women. Maternal listeriosis is a diagnostic challenge, and intrauterine infection can lead to severe complications such as amnionitis, preterm labor, spontaneous abortion, stillbirth and neonatal sepsis. From 2001 to 2005, 16 patients with L. monocytogenes were identified in this hospital; four (25%) were pregnant women. Clinical and laboratory findings are described. There were 3 preterm deliveries and 1 spontaneous second trimester abortion. Three women with listeriosis had no predisposing factors other than pregnancy. One patient was on immunosupressive drugs for ulcerative colitis. Fever was the most common symptom. Infected neonates were most commonly diagnosed with early-onset listeriosis (two cases) or fetal demise (one case). Pregnancy can be the only risk factor for listeriosis. Listeriosis should be considered during the evaluation of febrile syndrome in pregnancy as this condition can be the only risk factor. Blood and amniotic fluid cultures are useful diagnostic tests. Perinatal complications remains high.

Metallo-beta-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes.To detect the presence of MBL in imipenem resistant Psae strains.Fifty-nine imipenem resistant Psae strains isolated from January 2004 to August 2005 in a University Clinical Hospital, were included. The presence of MBL was studied by Etest (phenotypic) and genotypic polymerase chain reaction (PCR) methods. To rule out a nosocomial outbreak, MBL positive strains were studied by pulse field gel electrophoresis.The presence of MBL was detected in eleven strains. AH were type VIM and were not clonally related. There was no concordance between phenotypic and genotypic MBL detecting methods. All the strains were also multiresistant.The presence of MBL was detected in 19% of imipenem resistant Psae strains.

Congenital syphilis (CS) is an important health problem in Chile, with a rate of 0.25/1,000 live newborn (NB) during year 2004. In 2000, the Chilean Ministry of Public Health recommended to perform a screening in cord blood at the moment of delivery. Instead, the Centers for Disease Control and Prevention guidelines recommend the screening in maternal serum since cord blood has up to 5% of false (-) versus 0.5% of maternal serum, both with respect to the NB serum.Maternal serum and NB cord blood were studied during one year to determine the best screening method at delivery.RPR was performed and positive results were confirmed by treponemic test (immunochromatographyDetermine, ELISA Captia, Ig and IgM, and MHA-Tp). Serologically confirmed patients were evaluated by the specialist to define CS cases.Between June 1999 and August 2000 2,741 binomies were studied; of these, 37 (1.3%) were RPR reactive and 2.704 were non-reactive. In 11 of the 37 reactive cases, mother and NB were RPR reactive (Group I), in 9 cases the NB was RPR reactive and the mother was non-reactive (Group II), and the other 17 were NB non-reactive and mother reactive (Group III). In group I, 7/11 (64%) were true (+)s and 4/11(36%)) false (+)s of RPR. In group II, 9/9 (100%) corresponded to false (+)s of RPR in cord blood, and in group III, 11/17 (65%) corresponded to false (+)s of RPR in maternal blood but 6/17 (35%) were found to be cases of syphilis during pregnancy. Three of them were not treated opportunely and were designed as CS. In total 9 NB corresponded to CS (6 in group I and 3 in group III). If the screening had been performed only in cord blood, three NB with CS would have not been diagnosed.Even when maternal serum has a high rate of false (+)s, it has better sensitivity than cord blood for the diagnosis of CS, thus it is suggested to perform the screening at delivery with maternal serum instead of cord blood samples.

La sifilis congenita (SC) es un problema importante en Chile, con una tasa de 0,25/1.000 recien nacidos (RNs) vivos en el ano 2004. En el ano 2000, el Ministerio de Salud recomendaba como tamizaje al momento del parto una muestra de sangre de cordon. El Centro de Control y Prevencion de Enfermedades, (CDC), Atlanta, E.U.A. recomendo, desde 1998, el tamizaje al parto con suero materno ya que respecto del suero del RN, la sangre de cordon y el suero materno tienen respectivamente hasta 5 y 0,5%> de falsos negativos. Objetivo: Determinar el mejor tamizaje al momento del parto. Metodos: Se estudiaron muestras de suero materno y sangre de cordon de los RNs durante un ano. Se realizo RPR y de ser positiva, pruebas treponemicas confirmatorias (imunocromatografico Determine®, ELISA Captia® IgG e IgM y microhemaglutinacion). Todos los pacientes confirmados fueron vistos por el especialista para definir los casos de SC. Resultados: Entre junio de 1999 y agosto del 2000 se estudiaron 2.741 binomios madre-RN; de estos 37/2.704 (1,3%) fueron RPR reactivos. Once eran RPR reactivo en la madre y en el RN (Grupo I), 9 eran RPR reactivo en el RN y no reactivo en la madre (Grupo II) y 17 eran RN con RPR no reactivo y reactivo en la madre (Grupo III). En el Grupo I hubo 64%> (7/11) de verdaderos (+)s y 36% (4/11) de falsos (+)s del RPR. En el Grupo II, 9/ 9 (100%o), correspondieron a falsos (+)s del RPR en sangre de cordon y en el Grupo III, 11/17 (67%>) correspondieron a falsos (+)s del RPR en sangre materna pero hubo 6/17 (35%>) que correspondian a sifilis durante el embarazo y en tres de ellas no hubo tratamiento intra-embarazo, por lo que fueron catalogadas como SC y los RNs debieron ser tratados. En total hubo 9 RNs que correspondieron a SC (6 del grupo I y 3 del grupo III). Si solo se hubiese realizado tamizaje en sangre de cordon, 3 RNs con SC no se hubiesen diagnosticado. Conclusion: Si bien el suero materno tiene una tasa de falsos (+)s alta, tiene mejor sensibilidad que la sangre de cordon para el diagnostico de SC; por lo que se sugiere realizar el tamizaje al momento del parto con suero materno en vez de sangre de cordon

The diagnostic difficulties of brucellosis makes the evaluation of new diagnostic tests necessary.Evaluation of different commercial tests in the serological diagnosis of brucellosis by ELISA and immunocapture antibodies in a clinical series of patients with brucellosis of the Health Network of the Catholic University of Chile.All the serums received in the Laboratory of Microbiology for suspicion of brucellosis during five years were studied. Two groups were obtained, one that fulfilled diagnostic criteria for brucellosis [clinical evidence, and/or positive blood culture and/or seroagglutination test (SAT) in titers1/160] and the control group. Each serum sample was analyzed using irnmunocapture-agglutination test (Brucellacapt), ELISA IgM and IgG.Of 10 patients with brucellosis, the serologic results were: 8/10 positives for ELISA IgG, 7/10 for Brucellacapt and SAT, and 5/10 for ELISA IgM.ELISA IgG alone was superior than SAT. The combination ELISA IgG/ Brucellacapt reaches the best detection performance (9/10) and can be an alternative to SAT.

Introduccion: El diagnostico de brucelosis continua siendo complejo en la actualidad y se requieren nuevas pruebas de diagnostico. Objetivo: Evaluar pruebas comerciales para la determinacion serologica de anticuerpos anti Brucella sp mediante ELISA e inmunocaptura en una serie clinica de pacientes de la Red de Salud UC. Metodos: Estudio retrospectivo de pacientes cuyos sueros fueron recibidos en el laboratorio de Microbiologia para estudio serologico de brucelosis. Se obtuvieron 2 grupos, aquellos que cumplian criterios diagnosticos de brucelosis [cuadro clinico compatible, y/o hemocultivo positivo y/o serologia por seroaglutinacion en tubo (SAT) en titulos > 1/160] y el grupo control. Todos los sueros se analizaron mediante aglutinacion con inmunocaptura (Brucellacapt®), ELISA IgM y ELISA IgG. Resultados: De 10 pacientes con brucelosis, los resultados serologicos fueron: 8/10 positivos para ELISA IgG, 7/10 para Brucellacapt® y SAT y 5/10 para ELISA IgM. Discusion: ELISA IgG por si solo fue la mejor prueba para el diagnostico de brucelosis. La combinacion ELISA IgG+ Brucellacapt® alcanza un buen rendimiento de deteccion (9/10) y puede ser una alternativa a la SAT

Background: Metallo-s-lactamases (MBL) confer high resistance to carbapenems in Pseudomonas aeruginosa (Psae). They are encoded in mobile elements of different genes (VIM, IMP, SMP, GIM), along with other resistance genes. Aim: To detect the presence of MBL in imipenem resistant Psae strains. Material and methods: Fifty-nine imipenem resistant Psae strains isolated from January 2004 to August 2005 in a University Clinical Hospital, were included. The presence of MBL was studied by Etest (phenotypic) and genotypic polymerase chain reaction (PCR) methods. To rule out a nosocomial outbreak, MBL positive strains, were studied by pulse field gel electrophoresis. Results: The presente of MBL was detected in eleven strains. AH were type VIM and were not clonally related. There was no concordance between phenotypic and genotypic MBL detecting methods. AH the strains were also multiresistant. Conclusions: The presence of MBL was detected in 19% of imipenem resistant Psae strains

We report the first case of bacillary angiomatosis due to Bartonella quintana affecting a Chilean a HIV positive patient in Chile. He was a 27 years old, heterosexual male, indigent man known to be HIV positive serological status known from September, 2003, under irregular medical control. On April, 2005, he presented a progressive abscess in the frontal region and erythematous papules in the extremities, that extended to face, thorax and mucoses, becoming nodular and violaceous lesions. Bacillary angiomatosis diagnosis was initially sustained on account of the clinical manifestations, and was confirmed by serology and Warthin Starry staining from a skin biopsy. The etiological agent was identified as Bartonella quintana through universal RPC performed from a cutaneous nodule to detect 16S rRNA gen. Azithromycin plus ciprofloxacin was started, besides of anti retroviral therapy antiretroviral, with the lesions being progressively disappearing.

Reportamos el primer caso de angiomatosis bacilar por Bartonella quintana en un paciente con infección por VIH en nuestro país. Este corresponde a un hombre de 27 años, heterosexual, indigente, seropositivo para VIH conocido desde septiembre de 2003, en control irregular. En abril de 2005, el paciente desarrolló un aumento progresivo de volumen en la región frontal y aparición de pápulas eritematosas en las extremidades, que luego se extendieron a la cara, tórax y mucosas, tornándose nodulares y violáceas. El diagnóstico de angiomatosis bacilar se planteó inicialmente por el cuadro clínico del paciente, siendo confirmado por serología y tinción de Warthin Starry positiva en la biopsia de piel. El agente causal se identificó como Bartonella quintana por RPC universal para el gen del 16S ARNr de un nódulo cutáneo. Se inició terapia antimicrobiana con azitromicina y ciprofloxacina, además de terapia antiretroviral, con desaparición de las lesiones en forma progresiva

La infección por Campylobacter sp es una de las etiologías más comunes de gastroenteritis en el mundo, y en Chile ocuparía el tercer lugar entre las diarreas bacterianas en lactantes, según estudios previos. En nuestro país el cultivo no se realiza rutinariamente por su alto costo económico, siendo conocido que la tinción de Hucker puede ser una buena alternativa de pesquisa. El objetivo del estudio fue conocer la utilidad de la tinción de Hucker y estimar la frecuencia de Campylobacter sp en muestras de deposiciones. Se estudiaron 5.750 muestras de coprocultivos recibidas en el Labo-ratorio de Microbiología de la Red de Salud UC entre marzo del 2002 y mayo del 2004, en las cuales se realizó coprocultivo convencional y tinción de Hucker. Para la validación de la tinción de Hucker con el cultivo se sembró durante un mes todas las muestras para la búsqueda de Campylobacter sp, encontrando una sensibilidad de 37,5% y especificidad de 100%. En 115/5.750 muestras (2%) se observaron bacilos curvos sugerentes de Campylobacter sp por tinción de Hucker y se aislaron otros 233 entero patógenos (4%) que correspondieron a: Salmonella sp (151), Shigella sp (55), Escherichia coli enterohemorrágica (25) y Yersinia sp (2). De las tinciones de Hucker positivas 62,6% correspondieron a niños bajo 5 años y de éstas 63,8% a lactantes. Concluimos que la tinción de Hucker en un método sencillo y específico, aunque poco sensible, que permite aumentar el rendimiento de la detección microbiológica de patógenos entéricos en 33%. En este estudio, Campylobacter sp ocupó el segundo lugar después de Salmonella sp en muestras de deposiciones enviadas para cultivo, concentrándose en edades tempranas de la vida. La búsqueda activa de Campylobacter sp por medio del cultivo específico es fundamental para el diagnóstico etiológico de un síndrome diarreico agudo

Campylobacter infection is one of the most frequent causes of gastroenteritis in the world and the third in Chile according to some studies. The routinary culture for Campylobacter in our country is not performed because of its high cost, and it is known, that the Hucker stain is a reasonable screening alternative. The objective of this study was to know the utility of the Hucker stain and estimate the frequency of Campylobacter in stool samples. A total of 5,750 stool samples received in the Catholic University Health Net Microbiology Laboratories, from March 2002 to May 2004, were studied with conventional stool culture and Hucker stain. In order to validate the Hucker stain with culture, during one month, all the stool samples were also studied with Campylobacter culture, with 35% sensitivity and 100% specificity. In 115/5.750 samples (2%), curved bacilli suggesting Campylobacter were observed by Hucker stain, and another 233 enteropathogens (4%) which corresponded to: 151 Salmonella sp, 55 Shigella sp, 25 enterohemorrhagic E coli, and 2 Yersinia sp were isolated. When analyzing the patients in whom the Hucker stain was positive, 62.2% were younger than 5 years and of these, 63.8% were infants. We conclude that the Hucker stain is a simple and specific method, although not very sensitive, that allows us to increase the yield of diagnosing enteric pathogens in a 33%. Campylobacter sp was in the second place after Salmonella sp in stool samples, and most frequent in young children. The active search for Campylobacter by means of culture is fundamental in the diagnosis of acute diarrhea.

Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place.To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey.Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira.Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected.In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection.

Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections.To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics.Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime.All strains were sensible to telithromycin at a concentration -4 microg/ml. MIC 90 and its range for SPNS was 0.03 microg/ml (-0.004-0.12), for SPNI was 0.03 microg/ml (-0.004-025), for SPNR was 0.06 microg/ml (-0.004-0.25), for HIN was 2 microg/ml (0.12-4), for SP was 0.5 microg/ml (-0.004-2), for MC was 0.5 microg/ml (0.06-2) and for SAU was 0.25 microg/ml (0.06-0.25).All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections.

Rhodococcus equi, es un bacilo grampositivo intracelular que causa infecciones mayoritariamente en pacientes inmunodeprimidos. Reportamos el caso de una mujer de 52 años, en tratamiento de lupus eritematoso sistémico, con historia progresiva de 10 meses de evolución caracterizada por tos, disnea progresiva, expectoración muco-purulenta, ocasionalmente hemoptoica, fiebre intermitente, y pérdida de peso del 10%. Tuvo respuesta parcial a diversos cursos de tratamiento antimicrobiano y el seguimiento radiológico evidenció la aparición de múltiples focos de consolidación bilaterales, algunos de ellos nodulares. El estudio microbiológico de un lavado broncoalveolar y de una biopsia pulmonar percutánea permitió la identificación de R. equi y la histología de la biopsia pulmonar fue compatible. Recibió tratamiento antimicrobiano bi-asociado prolongado con buena respuesta clínica y radiológica. Se debe considerar este agente en el estudio de pacientes inmunocomprometidos que cursan con neumonías de evolución prolongada.

Background:Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place. Aim: To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey. Material and methods: Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira. Results: Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected. Conclusions: In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection

Background: Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections. Aim: To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics. Material and methods: Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime. Results: All strains were sensible to telithromycin at a concentration ­4 µg/ml. MIC 90 and its range for SPNS was 0.03 µg/ml (­0.004-0.12), for SPNI was 0.03 µg/ml (­0.004-025), for SPNR was 0.06 µg/ml (­0.004-0.25), for HIN was 2 µg/ml (0.12-4), for SP was 0.5 µg/ml (­0.004-2), for MC was 0.5 µg/ml (0.06-2) and for SAU was 0.25 µg/ml (0.06-0.25). Conclusions: All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections

In Chile, the emergence of drug-resistant strains of Streptococcus pneumoniae has complicated treatment decisions and may lead to treatment failures.to examine antimicrobial resistance trends among pneumococcal isolates from the Catholic University Hospital between 1997 and 2003.During a seven-year period, we examined 901 strains of S. pneumoniae isolated from sterile and non-sterile samples from adult and pediatric population.Overall, 20% of isolates showed intermediate resistance to penicillin (MIC: 0.12-1 microg/ml) y 10.8% high level of resistance to penicillin (MICor = 2 microg/ml). Pneumococcal resistance to penicillin did not change significantly during the study period, but it was more common in pediatric patients and isolates from non-sterile samples. No isolate had a MICor = 8 microg/ml for penicillin. Twenty one percent of pneumococcal strains were resistant to erythromycin, 41.6% to trimethoprim-sulfamethoxazole and 3.6% to chloramphenicol. Macrolides resistance tended to increase between 1997 and 2003. Fourteen percent of strains showed intermediate resistance (MIC: 1 microg/ml) and 2.5%, a high level of resistance to cefotaxime (MIC:or = 2 microg/ml). No isolate had a CIMor = 4 microg/ml for cefotaxime. Among those isolates with intermediate or high level of resistance to penicillin, there were significantly more isolates highly resistant to erythromycin, trimethoprim-sulfamethoxazole and cefotaxime.Multidrug-resistant pneumococci are common and are increasing in our country, particularly in pediatric population, probably associated to indiscriminate ambulatory prescription of antimicrobials.

La intensidad y duracion de la neutropenia post quimioterapia fueron identificadas en la decada del 60 como los factores de mayor relevancia predisponentes a infecciones en pacientes con cancer. A inicios de la decada del 70 se establecio un manejo estandarizado para todos los episodios de neutropenia febril (NF), consistente en hospitalizacion y terapia antimicrobiana intravenosa empirica, de amplio espectro, lo que se tradujo en una importante disminucion de la mortalidad por infecciones bacterianas en estos pacientes. En los ultimos 10 a 15 anos, distintos grupos de investigadores han considerado poco beneficiosas estas estrategias estandarizadas, que proporcionan un manejo uniforme a todos los pacientes con episodios de NF, independiente de la gravedad de estos. Asi, se acunaron en la decada pasada los conceptos de NF de alto y bajo riesgo, lo que ha permitido implementar estrategias terapeuticas diferenciadas segun el riesgo que entrane el episodio para cada paciente en particular. La Sociedad Chilena de Infectologia ha tenido la iniciativa de proponer, en un trabajo conjunto con dos programas gubernamentales: Programa Infantil de Drogas Antineoplasicas y Programa Adulto de Drogas Antineoplasicas y la Sociedad Chilena de Hematologia, un consenso de diagnostico, manejo terapeutico y prevencion de NF en adultos y ninos con cancer, considerando basicamente dos aspectos: el cambio de enfoque que esta patologia ha tenido en la ultima decada, lo que obliga a una revision sistematizada del tema, y en segundo lugar, una poblacion creciente de pacientes oncologicos, cada vez con mejores expectativas terapeuticas para su patologia de base, lo que exige ofrecer en forma acorde un muy buen manejo de esta complicacion. Entregamos este documento con una completa revision de la literatura medica sobre epidemiologia, exploracion de laboratorio, categorizacion de riesgo, enfoque terapeutico y quimioprofilaxis, con la mayor cantidad de datos nacionales disponibles, para ofrecer al equipo de salud que atiende a estos pacientes recomendaciones basadas en evidencias, y acotadas a nuestra realidad nacional

Background: In Chile, the emergence of drug-resistant strains of Streptococcus pneumoniae has complicated treatment decisions and may lead to treatment failures. Aim: to examine antimicrobial resistance trends among pneumococcal isolates from the Catholic University Hospital between 1997 and 2003. Material and methods: During a seven-year period, we examined 901 strains of S. pneumoniae isolated from sterile and non-sterile samples from adult and pediatric population. Results: Overall, 20% of isolates showed intermediate resistance to penicillin (MIC: 0.12-1 µg/ml) y 10.8% high level of resistance to penicillin (MIC ³ 2 µg/ml). Pneumococcal resistance to penicillin did not change significantly during the study period, but it was more common in pediatric patients and isolates from non-sterile samples. No isolate had a MIC ³ 8 µg/ml for penicillin. Twenty one percent of pneumococcal strains were resistant to erythromycin, 41.6% to trimethoprim-sulfamethoxazole and 3.6% to chloramphenicol. Macrolides resistance tended to increase between 1997 and 2003. Fourteen percent of strains showed intermediate resistance (MIC: 1 µg/ml) and 2.5%, a high level of resistance to cefotaxime (MIC: ³ 2 µg/ml). No isolate had a CIM ³ 4 µg/ml for cefotaxime. Among those isolates with intermediate or high level of resistance to penicillin, there were significantly more isolates highly resistant to erythromycin, trimethoprim-sulfamethoxazole and cefotaxime. Conclusions: Multidrug-resistant pneumococci are common and are increasing in our country, particularly in pediatric population, probably associated to indiscriminate ambulatory prescription of antimicrobials (Rev Méd Chile 2005; 133: 42-49)

El uso de los implantes de tejido en medicina ha mejorado el pronóstico y/o la calidad de vida de muchas enfermedades, sin embargo, su utilización no está exenta de riesgos para el receptor. Es por esto que la cuidadosa selección del donante vivo o cadáver y el control microbiológico de los tejidos antes de su utilización son procesos muy importantes para asegurar la calidad del procedimiento. La contaminación de los tejidos puede ser intrínseca (por una infección no diagnosticada en el donante) o extrínseca (una vez que el tejido ya ha sido procurado). Estas recomendaciones se refieren al control microbiológico de las contaminaciones extrínsecas, ya sea durante la manipulación, durante la obtención de los tejidos o durante el procesamiento para la preservación de ellos. Se analizan los implantes de uso más frecuente en nuestro país (válvulas cardíacas, tejido óseo, piel, células progenitoras hematopoyéticas y córnea) y se describe la metodología según datos existentes en la literatura y de procedimientos adaptados de centros foráneos. Dado que ningún implante es absolutamente estéril es muy importante analizar también las recomendaciones frente a cultivos contaminados. Los autores esperamos que este documento sea de utilidad y que en un futuro próximo, podamos exhibir cifras nacionales multicéntricas con metodologías comparables

Background : Influenza-A (IA) occurs every winter, is mostly observed among outpatients. Aim: To describe the clinical and epidemiological characteristics of cases that required hospital admission during an outbreak in Chile in 1999. Patients and methods: Adults subjects, with Influenza A confirmed by antigen detection test, hospitalized in the clinical hospital of the «Hospital Clínico de la Universidad Católica de Chile» between May and June, with fever or respiratory symptoms were studied. A special record was designed to register clinical, microbiological and therapeutic data. Results: Fifty five cases, 26 males, aged 15 to 91 years, were studied. Eighty four percent had chronic concomitant diseases and 9.1% were immunosuppressed. Clinical findings were fever in 87.3%, asthenia in 83.6%, cough in 93.6%, abnormal pulmonary signs in 69%, an elevated C-reactive protein (mean value of 11.6 ± 7.1 mg/dL) and acute respiratory insufficiency in 54.5%. Cases were isolated in cohort or individual rooms and 38.2% were admitted to intensive or intermediate care units. Amantadine was prescribed to 52 patients and was well tolerated. Thirty three percent of cases developed pneumonia. These subjects were older, had more dyspnea and respiratory insufficiency than patients without pneumonia. Conclusions: IA should be borne in mind when dealing with hospitalized adults, during epidemic outbreaks in the community. The clinical picture can resemble a serious bacterial infection. An early diagnosis allows the use of specific treatments, to decrease the risk of nosocomial spread and to avoid unnecessary use of antibiotics (Rev Méd Chile 2004; 132: 317-24).

Streptococcus grupo anginosus, y sus especies constellatus, anginosus e intermedius, causan infecciones supuradas. Su identificación microbiológica es compleja pues pueden ser beta-hemolíticos y comparten antígenos de Lancefield con otros estreptococos. Si bien morfológicamente son colonias pequeñas y presentan un olor característicos, si sólo se realiza test de látex para aglutinación del carbohidrato C pueden ser clasificados erróneamente. El objetivo de nuestro trabajo fue evaluar un algoritmo que utiliza 3 pruebas bioquímicas, conocer su susceptibilidad a antimicrobianos y describir las características clínicas de infecciones producidas por Streptococcus grupo anginosus. Se estudiaron cepas de Streptococcus grupo C, G y F, determinando sus características morfológicas de colonia, para identificar cepas de colonia pequeña que se incluyeron en el algoritmo de bajo costo propuesto (b-glucuronidasa y el test Voges-Proskauer) comparándose al método API Rapid ID 32 Strept®, establecido como estándar de oro. Se estudiaron 219 cepas, de las cuales 101 presentaron las características morfológicas compatibles con grupo anginosus, identificándose S. constellatus en 58% (59/101), S. anginosus en 37% (37/101) y S. intermedius en 5% (5/101). Las cepas aisladas procedían principalmente de infecciones piogénicas (61%, 62/101), en especial de foco abdominal. Se observó 98% de susceptibilidad a penicilina y cefotaxima y resistencia a eritromicina y clindamicina en 6,8 y 5%, respectivamente. La edad promedio de los pacientes fue de 30 años (2-85), con distribución similar por sexo y predominio de pacientes hospitalizados. Los resultados expuestos demuestra la efectividad del algoritmo de bajo costo para la detección de S. grupo anginosus. En nuestra experiencia este grupo bacteriano conserva su susceptibilidad a penicilina y cefotaxima, siendo necesario vigilar clindamicina y eritromicina

El Instituto de Salud Pública de Chile y la Sociedad Chilena de Infectología han aunado sus esfuerzos para coordinar y co-dirigir una red nacional para la vigilancia de resistencia de agentes patógenos a antimicrobianos según síndromes clínicos. El objetivo de esta red es establecer un sistema nacional de vigilancia de la resistencia a antimicrobianos, estandarizado y coordinado, que proporcione información actualizada acerca de los agentes infecciosos más relevantes por síndromes clínicos bien definidos, por edad y por lugar de origen: hospitalaria o de la comunidad. Nos parece fundamental la participación de todos los Servicios de Salud del país en esta red, para obtener datos de calidad, representativos de nuestra realidad nacional, que sean de real utilidad en el manejo de los pacientes.

Los cateteres intravasculares son dispositivosplasticos que permiten acceder al compartimientointravascular a nivel central. Varian en su disenoy estructura segun se utilicen en forma temporal(dias) o permanente (semanas, meses) asi comotambien en el material con que son fabricados, enel numero de lumenes, y en el motivo por el cualse instalan.El uso de estos dispositivos ha sido de granutilidad clinica ya que permiten un acceso rapidoy seguro al torrente sanguineo, pudiendo serutilizados para la administracion de fluidosendovenosos, medicamentos, productos sangui-neos, nutricion parenteral total, monitoreo delestado hemodinamico y para hemodialisis. Sinembargo, no estan exentos de riesgos habiendosedescrito complicaciones mecanicas e infecciosas.La infeccion relacionada a cateteres centralesconstituye una de las principales complicacionesde su uso y la primera causa de bacteriemianosocomial primaria. La incidencia de bacteriemiaatribuible a su uso es variable entre distintoscentros hospitalarios. Dada la importancia deestas infecciones, tanto en morbimortalidad comoen los costos asociados, resulta fundamental con-tar con un consenso para el diagnostico de lainfeccion relacionada a dispositivos vasculares,que permita tomar conductas adecuadas tantopara su prevencion como en el tratamiento.

La resistencia bacteriana es un fenómeno complejo en que influyen factores como el uso y abuso de los antimicrobianos, el debilitamiento de los programas de control de infecciones y la existencia de pacientes complejos multi-invadidos. Dado que la resistencia bacteriana tiene como principal consecuencia el fracaso de la terapia antimicrobiana, el aumento de la morbi-mortalidad y el aumento en los costos de la atención médica, resulta indispensable la contención del problema. La etapa inicial de la contención es conocer la magnitud de la resistencia bacteriana, lo que en nuestro país ha resultado difícil por carecer de un sistema nacional de registro, unificado, de gran cobertura y con una calidad certificada. Con los datos disponibles a la fecha obtenidos de diversas fuentes de información, resulta preocupante la emergencia de resistencia en Staphylococcus aureus a meticilina, en Streptococcus pneumoniae a penicilina, en Escherichia coli y Klebsiella pneumoniae a cefalosporinas de tercera generación y de Pseudomonas aeruginosa a imipenem. En estos últimos aspectos es preocupante el aumento progresivo de resistencia de E. coli y K. pneumoniae a cefalosporinas de tercera generación por beta lactamasas de espectro extendido, que confieren resistencia a todos los beta lactámicos, cuyos test confirmatorios están escasamente implementados en nuestro país. Respecto de la resistencia de P. aeruginosa a carbapemémicos aún no es un problema de gran magnitud en Chile, pero en hospitales de alta complejidad deben existir terapias alternativas y métodos que permitan la confirmación de la resistencia a este antimicrobiano. En suma, queda manifiesta la absoluta necesidad de conocer en forma representativa y certificada las cifras de resistencia a los diferentes antimicrobianos, para adoptar las medidas terapeúticas necesarias

RESUMENStreptococcus agalactiae es el principal agente causal de sepsis neonatal de aparicion precoz con unaincidencia que fluctua entre 1 y 3 por 1000 recien nacidos vivos. Se han entregado pautas dirigidas a reducirlas tasas de sepsis precoz con la administracion de antibioticos intraparto. Se ha propuesto como antibioticode primera eleccion la Penicilina o Ampicilina, y Clindamicina para pacientes alergicos a las primeras, perotambien se ha planteado el uso de Eritromicina o Cefazolina. Se estudia la sensibilidad a estas drogas, en183 cepas de Streptococcus Grupo B, aisladas en 917 embarazadas, al final del tercer trimestre, en regionvaginal y perianal.PALABRAS CLAVES: Streptococcus grupo Beta, antibioticos sensibilidadSUMMARYStreptococcus agalactiae (Grupo B Streptococcus) is the main bacterial agent involved in neonatalsepsis of early onset (1 to 3/1000 live newborns). Has been given standards for reducing the rates ofneonatal sepsis of early onset using antibiotics during labor. Has been proposed as the first choice Penicilinor Ampicilin and Clindamicin for allergic patients. Erythromycin and Cefazolin has been proposed to treatthis patients.This report study sensibilities for this drugs in 183 Group B Streptococcus strains from vaginal andperianal region of 917 pregnant women during the last trimester.KEY WORDS: Group B Streptococcus, antibiotic sensibilities

We report the case of a 70 year-old-man with history of non-insulin dependant diabetes, arterial hypertension and chronic renal failure in hemodyalisis who was admitted to hospital with a history of fever for three weeks. Aseptic arthritis of the left hip was diagnosed an a surgical debridement was performed. Cultures showed growth of a fastidious gram-negative cocobacilus. The patient was re-admitted because of impaired consciousness, an acute myocardial infarction and fever. Brain CT scan and head MRI were normal as well as cerebrospinal fluid analysis. Final identification of the gram negative rod corresponded to Psychrobacter phenylpyruvicus (formerly Moraxella phenylpyruvicus). Treatment with ceftriaxone was begun. After two weeks the patient died of cardiac arrest. Moraxellaceae family is part of the normal flora of the upper respiratory tract and genitourinary tract. Occasionally Moraxellaceae family is seen as a pathogen. There are only two previous reports of infections due to Psychrobacter phenylpyruvicus, a diabetic foot and an infectious endocarditis, this is the first case of septic arthritis caused by this microorganism.

El diagnóstico rápido de microorganismos presentes en fluidos corporales estériles es de gran importancia clínica. La tinción de Gram constituye la principal herramienta para el diagnóstico de estas infecciones, pero la sensibilidad de esta técnica varía según el tipo de muestra y la carga bacteriana presente en ella. La concentración de la muestra previa a la tinción, mejora el rendimiento pero requiere volúmenes significativos de la muestra. La citocentrifugación resulta útil ya que requiere escaso volumen de muestra y permite obtener preparaciones uniformemente concentradas. Con el objetivo de evaluar la utilidad de la citocentrifugación en el diagnóstico de infecciones de fluidos corporales, se estudiaron 52 muestras de fluidos de cavidades estériles recibidas en el Laboratorio de Urgencia del Servicio de Laboratorios Clínicos de la Red de Salud UC. Las muestras fueron separadas para centrifugación convencional (CC) a 3000 rpm por 5 minutos (centrífuga Jouan CR3i ®) y para citocentrifugación (CT) a 2000 rpm por 10 minutos (Citocentrífuga Cytospin Shandon Inc®). Del sedimento obtenido por CC se realizó un frotis para tinción de Gram y cultivo. De la CT se obtuvo una mono capa celular concentrada en un área de 6 mm de diámetro para tinción de Gram. Ambos frotis fueron leídos por el mismo observador. De las 52 muestras analizadas, 18 fueron sugerentes de infección clínica. La sensibilidad para CT v CC fue de 89% y 61%, respectivamente. La especificidad fue de 100% para ambas técnicas. En una evaluación cuantitativa de la celularidad de las muestras, se observó un aumento de los leucocitos en la CT con respecto a CC. Estos resultados muestran que la CT puede ser de gran ayuda en el diagnóstico rápido de las infecciones de fluidos corporales con baja carga bacteriana. Presenta una mayor sensibilidad y facilita la visualización de bacterias, especialmente en muestras con bajo recuento celular The rapid diagnosis of microorganisms found in body fluids is clinically relevant. The Gram stain technique represents the main tool for this diagnosis but its sensitivity varies according to the sample type and the bacterial burden. Concentrating the sample enhances the stain sensitivity but a significant samples volume is required. Cytocentrifugation (CT) is useful because it requires less samples volume, thus obtaining more homogenous and concentrated preparations. To evaluate CT for diagnosis of body fluids, 52 samples obtained from sterile cavities were studied at the Emergency Laboratory at Pontificia Universidad Católica de Chile. The samples were processed with conventional centrifugation (CC) at 3000 rpm for 5 minutes and with CT at 2000 rpm for 10 minutes. From the sediment obtained through CC a smear for Gram staining and culture was done. From the sediment obtained by CT, a cellular monolayer in a 6 mm area was prepared for Gram staining. Both smears were analyzed by the same operator. Of 52 samples studied, 18 suggested clinical infection. Sensitivity for CT was 89 %, whereas sensitivity for CT showed 100%. Specificity was 100% in both methods. An increase in cellular concentration of samples was observed with CT compared to CC. These results confirm the usefulness of CT for a rapid diagnosis of samples with low bacterial burden. Cytocentrifugation has higher sensitivity than CC and enhances bacterial observation in Gram stained samples, especially in samples with a low cellular concentration

One of the most frecuent complications of enteral nutrition is formula contamination. The objective of this study was to evaluate the frequency and routes by which enteral formula contamination occurs. Two types of formula were evaluated, one powdered and one liquid, with sterile re-used containers. The results show that the most important way of contamination is in the formula-preparing unit by manipulation or use of contaminated utensils. The utilization of re-used containers contributes to contamination in a lesser degree. The solution administration sets have a high degree of contamination, over 85% and this is not modified by the use of sterile material. Probably there is also a retrograde contamination mechanism.