Origin, genomic diversity and microevolution of the Clostridium difficile B1/NAP1/RT027/ST01 strain in Costa Rica, Chile, Honduras and Mexico.

Clostridium difficile B1/NAP1/RT027/ST01 has been responsible for outbreaks of antibiotic-associated diarrhoea in clinical settings worldwide and is associated with severe disease presentations and increased mortality rates. Two fluoroquinolone-resistant (FQR) lineages of the epidemic B1/NAP1/RT027/ST01 strain emerged in the USA in the early 1990s and disseminated trans continentally (FQR1 and FQR2). However, it is unclear when and from where they entered Latin America (LA) and whether isolates from LA exhibit unique genomic features when compared to B1/NAP1/RT027/ST01 isolates from other regions of the world. To answer the first issue we compared whole-genome sequences (WGS) of 25 clinical isolates typed as NAP1, RT027 or ST01 in Costa Rica (n=16), Chile (n=5), Honduras (n=3) and Mexico (n=1) to WGS of 129 global isolates from the same genotype using Bayesian phylogenomics. The second question was addressed through a detailed analysis of the number and type of mutations of the LA isolates and their mobile resistome. All but two B1/NAP1/RT027/ST01 isolates from LA belong to the FQR2 lineage (n=23, 92 %), confirming its widespread distribution. As indicated by analysis of a dataset composed of 154 WGS, the B1/NAP1/RT027/ST01 strain was introduced into the four LA countries analysed between 1998 and 2005 from North America (twice) and Europe (at least four times). These events occurred soon after the emergence of the FQR lineages and more than one decade before the first report of the detection of the B1/NAP1/RT027/ST01 in LA. A total of 552 SNPs were identified across all genomes examined (3.8-4.3 Mb) in pairwise comparisons to the R20291 reference genome. Moreover, pairwise SNP distances were among the smallest distances determined in this species so far (0 to 55). Despite this high level of genomic conservation, 39 unique SNPs (7 %) in genes that play roles in the infection process (i.e. slpA) or antibiotic resistance (i.e. rpoB, fusA) distinguished the LA isolates. In addition, isolates from Chile, Honduras and Mexico had twice as many antibiotic resistance genes (ARGs, n=4) than related isolates from other regions. Their unique set of ARGs includes a cfr-like gene and tetM, which were found as part of putative mobile genetic elements whose sequences resemble undescribed integrative and conjugative elements. These results show multiple, independent introductions of B1/NAP1/RT027/ST01 isolates from the FQR1 and FQR2 lineages from different geographical sources into LA and a rather rapid accumulation of distinct mutations and acquired ARG by the LA isolates.

Evaluación de un test comercial de avidez de IgG: Aporte al diagnóstico de primoinfección por Toxoplasma gondii / Evaluation of an IgG avidity commercial test: Contribution to diagnosis of primary infection caused by Toxoplasma gondii

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 percent (n: 11) were IgM positive and 100 percent (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 percent 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.

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 por ciento (n: 11) tuvieron IgM positivo y 100 por ciento (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 por ciento 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.

[Evaluation of an IgG avidity commercial test: contribution to diagnosis of primary infection caused by Toxoplasma gondii]. / Evaluación de un test comercial de avidez de IgG: Aporte al diagnóstico de primoinfección por Toxoplasma gondii.

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.

[Malaria: report of 12 non autochthonous cases]. / Malaria: revisión retrospectiva de 12 casos no autóctonos en Chile.

Malaria is a protozoan infection caused by four Plasmodia species transmitted by female Anopheles mosquito. Nearly 40% of the world population is at risk of acquiring the disease because of increasing resistance to treatment, climate changes and travels to endemic zones. We report twelve patients with diagnosis of malaria, supported by the identification of parasites on blood smear. All cases had traveled to endemic zones (Peru, Ecuador, Central America, Africa), but only three used chemoprophylaxis. Seven cases were infected with Plasmodium vivax and five cases with P. falciparum. Three of latter required intensive care. All patients were treated with standard drugs according to the severity and Plasmodium specie, with excellent results and no mortality.

[Clinical and epidemiological characteristics of respiratory virus infections among adults hospitalized during 2004 influenza season]. / Perfil clínico-epidemiológico de las infecciones por virus respiratorios en adultos hospitalizados durante la estación de influenza 2004.

BACKGROUND: During yearly influenza (FLU) season, FLU viruses are well represented among hospitalized patients as in the community. Also, other respiratory viruses could be represented among adult in-patients. AIM: to describe the presence and clinical- epidemiological characteristics of non-FLU respiratory virus infections (respiratory syncytial-RSV, parainfluenza and adenovirus-ADV) among hospitalized adults during FLU season and to compare with FLU-A (IA) or -B (IB) cases. PATIENTS AND METHODS: Adult patients hospitalized at Hospital Clínico Universidad Católica between May to July 2004 with a respiratory virus infections confirmed by rapid antigen test or direct immunofluorescence of IA, IB (Flu group) or RSV, parainfluenza (1-2-3) and ADV (non-Flu group) were included. RESULTS: 86 cases were identified: 73.5% FLU (48.2% IA, 25.3% IB) and 26.5% non-FLU (15.7% parainfluenza-2; 8.4% RSV; 1.2% parainfluenza-3; 1.2% ADV). No differences were observed in general characteristics and evolution of patients. In FLU-group were more frequently observed myalgia, cough, hospitalization due to febrile syndrome, higher values of C-reactive protein and band leukocytes count (p < 0.05). CONCLUSIONS: During 2004 FLU season a 26.5 % of respiratory viral infection were due to non-FLU viruses among adult hospitalized in our centre. The difficulty to difference FLU vs. non-FLU infections, suggest that it is necessary to include other respiratory virus in the viral etiological diagnosis, even in FLU season.

Malaria: revisión retrospectiva de 12 casos no autóctonos en Chile / Malaria: Report of 12 non autochthonous cases

Malaria is a protozoan infection caused by four Plasmodia species transmitted by female Anopheles mosquito. Nearly 40% of the world population is at risk of acquiring the disease because of increasing resistance to treatment, climate changes and travels to endemic zones. We report twelve patients with diagnosis of malaria, supported by the identification of parasites on blood smear. All cases had traveled to endemic zones (Peru, Ecuador, Central America, Africa), but only three used chemoprophylaxis. Seven cases were infected with Plasmodium vivax and five cases with P. falciparum. Three of latter required intensive care. All patients were treated with standard drugs according to the severity and Plasmodium specie, with excellent results and no mortality.

Perfil clínico-epidemiológico de las infecciones por virus respiratorios en adultos hospitalizados durante la estación de influenza 2004 / Clinical and epidemiological characteristics of respiratory virus infections among adults hospitalized during 2004 influenza season

El comportamiento epidemiológico del virus influenza (FLU) en la comunidad se refleja en el hospital, es planteable que la actividad comunitaria de otros virus respiratorios también se traduzca en un alza de las internaciones por estos agentes. Objetivo: describir la presencia y características clínico-epidemiológicas de infecciones por virus respiratorios no-FLU (virus respiratorio sincicial-VRS, parainfluenza y adenovirus-ADV) entre adultos hospitalizados durante la temporada de influenza y establecer una comparación con virus influenza-A (IA) o -B (IB). Pacientes y Método: Adultos internados en Hospital Clínico Universidad Católica, de mayo a julio de 2004, con infección por IA o IB, y VRS, parainfluenza (1-2-3) o ADV demostrada por test rápido o inmunofluorescencia directa. Resultados: Se identificaron 86 casos: 73,5 por ciento FLU (48,2 por ciento, IA y 25,3 por ciento IB) y 26,5 por ciento no-FLU. (15,7 por ciento parainfluenza-2; 8,4 por ciento VRS, 1,2 por ciento parainfluenza-3 y 1,2 por ciento ADV). El grupo con FLU presentó más frecuentemente mialgias, tos, hospitalización por síndrome febril, mayores valores de PCR y porcentaje de baciliformes (p < 0,05). Conclusiones: Durante la temporada de influenza 2004, 26,5 por ciento de las infecciones entre adultos hospitalizados fueron causadas por virus no-FLU. La dificultad en diferenciar infecciones por virus FLU de no-FLU, plantea la necesidad de ampliar el estudio de la etiología viral incluso durante la temporada de FLU.

Consenso: manejo racional del paciente con cáncer, neutropenia y fiebre / Consensus: rational approach towards the patient with cancer, fever and neutropenia

La intensidad y duración de la neutropenia post quimioterapia fueron identificadas en la década del 60 como los factores de mayor relevancia predisponentes a infecciones en pacientes con cáncer. A inicios de la década del 70 se estableció un manejo estandarizado para todos los episodios de neutropenia febril (NF), consistente en hospitalización y terapia antimicrobiana intravenosa empírica, de amplio espectro, lo que se tradujo en una importante disminución de la mortalidad por infecciones bacterianas en estos pacientes. En los últimos 10 a 15 años, 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. Así, se acuñaron en la década pasada los conceptos de NF de alto y bajo riesgo, lo que ha permitido implementar estrategias terapéuticas diferenciadas según el riesgo que entrañe el episodio para cada paciente en particular. La Sociedad Chilena de Infectología ha tenido la iniciativa de proponer, en un trabajo conjunto con dos programas gubernamentales: Programa Infantil de Drogas Antineoplásicas y Programa Adulto de Drogas Antineoplásicas y la Sociedad Chilena de Hematología, un consenso de diagnóstico, manejo terapéutico y prevención de NF en adultos y niños con cáncer, considerando básicamente dos aspectos: el cambio de enfoque que esta patología ha tenido en la última década, lo que obliga a una revisión sistematizada del tema, y en segundo lugar, una población creciente de pacientes oncológicos, cada vez con mejores expectativas terapéuticas para su patología de base, lo que exige ofrecer en forma acorde un muy buen manejo de esta complicación. Entregamos este documento con una completa revisión de la literatura médica sobre epidemiología, exploración de laboratorio, categorización de riesgo, enfoque terapéutico 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.