Predictors of poor outcomes in young non-comorbid patients with COVID-19

ABSTRACT Background: Prognostic factors in previously healthy young patients with COVID-19 remained understudied. Objective: The objective of the study was to identify factors associated with in-hospital death or need for invasive mechanical ventilation (IMV) in young (aged ≤ 65 years) and previously healthy patients with COVID-19. Methods: We conducted a prospective cohort study that included patients admitted with COVID-19. The primary outcome was in-hospital death/need for IMV. Secondary outcomes included need for IMV during follow-up, days on IMV, length of stay (LOS), hospital-acquired pneumonia/ventilator-associated pneumonia (HAP/VAP), and pulmonary embolism (PE). Bivariate and multivariate analyses were performed. Results: Among 92 patients, primary outcome occurred in 16 (17%), death in 12 (13%), need for IMV in 16 (17%), HAP/VAP in 7 (8%), and PE in 2 (2%). Median LOS and IMV duration were 7 and 12 days, respectively. Independent associations were found between the primary outcome and male sex (Adjusted odds ratio [aOR] 7.1, 95%CI 1.1-46.0, p < 0.05), D-dimer levels > 1000ng/mL (aOR 9.0, 95%CI 1.6-49.1, p < 0.05), and RT-PCR Ct-value ≤ 24 on initial swab samples (aOR 14.3, 95%CI 2.0-101.5, p < 0.01). Conclusions: In young and non-comorbid COVID-19 patients, male sex, higher levels of D-dimer, and low SARS-CoV-2 RT-PCR Ct-value on an initial nasopharyngeal swab were independently associated with increased in-hospital mortality or need for IMV.

Prevención de eventos de superpropagación de COVID-19 en autobuses que transportaron pacientes presintomáticos / Prevention of COVID-19 superspreader events in buses boarded by presymptomatic patients

Resumen Introducción: Ha ocurrido superpropagación de COVID-19 cuando individuos sintomáticos sin uso de cubrebocas abordaron autobuses. Objetivo: Reportar el riesgo de superpropagación cuando individuos presintomáticos abordaron autobuses junto con pasajeros no vacunados, pero se mantuvieron intervenciones preventivas no farmacológicas. Métodos: Estudio prospectivo de personal de salud transportado durante dos semanas en autobuses a un centro de vacunación contra COVID-19. Fue obligatorio llevar ventanas abiertas, uso correcto de cubrebocas y exclusión de personas con síntomas. La vigilancia prospectiva identificó a trabajadores con COVID-19 los 14 días siguientes a la vacunación. Cada pasajero asintomático de autobuses donde se detectaron casos fue vigilado durante un periodo similar. Los resultados de tamizaje voluntario estuvieron disponibles para los trabajadores que se realizaron prueba el mes previo o el siguiente a la vacunación. Resultados: 1879 trabajadores abordaron 65 autobuses. El tiempo a bordo varió de tres a ocho horas. Veintinueve casos de COVID-19 y cuatro casos asintomáticos fueron identificados entre 613 pasajeros de 21 autobuses. La mediana de tiempo entre la vacunación y el inicio de síntomas de COVID-19 fue de seis días. Fue identificado un caso de transmisión sospechada en autobús. Conclusiones: Las intervenciones preventivas no farmacológicas estrictas redujeron sustancialmente el riesgo de superpropagación de COVID-19 en autobuses ocupados por individuos presintomáticos.

Abstract Introduction: COVID-19 superspreader events have occurred when symptomatic individuals without wearing face masks boarded buses. Objective: To report the risk of superspreader events when presymptomatic individuals boarded buses together with unvaccinated passengers, but with non-pharmacological preventive interventions being maintained. Methods: Prospective study of health personnel transported in buses to a COVID-19 vaccination center for two weeks. Open windows, correct use of face masks and exclusion of symptomatic individuals were mandatory. Prospective surveillance identified workers with COVID-19 within 14 days after vaccination. Each asymptomatic passenger of buses where cases were identified was monitored for a similar time period. Voluntary screening results were available for workers who were tested in the month before or after vaccination. Results: 1,879 workers boarded 65 buses. On-board time ranged from three to eight hours. Twenty-nine cases of COVID-19 and four asymptomatic cases were identified among 613 passengers of 21 buses. Median time between vaccination and COVID-19 symptoms onset was six days. One case of suspected transmission on a bus was identified. Conclusions: Strict nonpharmacological preventive interventions substantially reduced the risk of COVID-19 superspreader events in buses boarded by presymptomatic individuals.

Significant Rise in SARS-CoV-2 Reinfection Rate in Vaccinated Hospital Workers during the Omicron Wave: A Prospective Cohort Study

ABSTRACT Background: Relatively low SARS-CoV-2 reinfection rates have been reported in vaccinated individuals, but updates considering the Omicron variant are lacking. Objective: The objective of the study was to provide a current estimate of the SARS-CoV-2 reinfection rate in a highly immunized population. Methods: A prospective cohort of Mexican hospital workers was followed (March 2020-February 2022). Reinfection was defined as the occurrence of two or more episodes of COVID-19 separated by a period of ≥ 90 days without symptoms. The reinfection rate was calculated as the number of reinfection episodes per 100,000 persons per day. Results: A total of 3732 medical consultations were provided to 2700 workers, of whom 1388 (51.4%) were confirmed COVID-19 cases. A total of 73 reinfection cases were identified, of whom 71 (97.3%) had completed their primary vaccination series and 22 (30.1%) had had a booster dose before the second episode. The overall reinfection rate was 23.1 per 100,000 persons per day (as compared to a rate of 1.9 per 100,000 persons per day before the Omicron wave). Conclusions: The SARS-CoV-2 reinfection rate rose significantly during the Omicron wave despite a high primary vaccination coverage rate. Almost one-third of reinfected workers had a vaccine booster ≥ 14 days before the last COVID-19 episode.

Surge in Ventilator-Associated Pneumonias and Bloodstream Infections in An Academic Referral Center Converted to Treat COVID-19 Patients

Background: Healthcare-associated infections (HAIs) are important adverse events that must be prevented. Objective: The objective of the study was to report and study possible changes in HAI rates as well as their causes after the COVID-19 hospital surge capacity response (HSCR) in an academic referral center. Methods: This was a before-after observational study. The Infection Prevention and Control (IPC) program (prospective surveillance, prevention bundles, antibiotic stewardship, continuing education, and feedback) was transiently disrupted after the start of HSCR (March 2020). HAI rates were compared before (January 2019-February 2020) and after (April-July 2020) HSCR, and plausible predisposing factors in affected patients were compared. Results: An increase in the HAI rate from 6.2 to 11.8 cases/1000 patient-days was noted between periods due to increases in ventilator-associated pneumonia and bloodstream infection (BSI) rates. More critically ill patients were admitted during HSCR, and use of invasive devices increased. Prone positioning and infusion of muscle relaxants became commonplace. The nurse-to-patient ratio in the intensive care unit decreased, and 4 h shifts were introduced to avoid fatigue. The BSI rate decreased after the IPC program with additional measures was reintroduced in May 2020. Conclusions: The strain on the workforce and modifications to the IPC program very possibly underlay the findings. IPC programs continue to be essential during the pandemic.

Factors Associated with COVID-19 and Asymptomatic Carriage in Healthcare Workers of a COVID-19 Hospital

ABSTRACT Background: Risk factors for coronavirus disease (COVID-19) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) asymptomatic carriage (AC) in healthcare workers (HCWs) have been scarcely characterized. Objective: The objective of the study was to study factors associated with COVID-19 and AC in HCWs of a COVID-19 academic medical center. Methods: This is a case-control study. Cases were either symptomatic or asymptomatic HCWs with a positive SARS-CoV-2 polymerase chain reaction (PCR) test result between March 16 and May 21 of 2020. Adjusted odds ratios (aOR) were calculated by means of multivariable logistic regression. In addition, each subject was followed for 14 days to inform outcomes. Results: One hundred thirty of 249 (52.2%) symptomatic HCWs had COVID-19; 10 were hospitalized but none died. Of 987 asymptomatic HCWs, 37 (3.7%) were AC; 6 of the remaining 950 asymptomatic HCWs with a negative PCR test result were found to be presymptomatic COVID-19 cases the following 14 days. Nurses were more frequently present in the COVID-19 group (51.5% vs. 37.0%), but multivariable analysis rendered non-significant results. After adjustment for age, comorbidities, and working place, factors found to be associated with AC were: working in wards as a nurse (aOR = 9.19, 95% confidence interval [CI] = 1.05-80.22, p = 0.045), kitchen personnel (aOR = 4.09, 95% CI = 1.55-10.83, p = 0.005), and being a physician (aOR = 0.12, 95% CI = 0.03-0.54, p = 0.006). Conclusions: HCW category was the predominant factor associated with AC of SARS-CoV-2 in this study.

Nontuberculous mycobacterial infection in a tertiary care center in Mexico, 2001-2017

ABSTRACT Introduction: Nontuberculous mycobacteria (NTM) comprise several pathogens with a complex profile of virulence, diverse epidemiological and clinical patterns as well as host specificity. Recently, an increase in the number of NTM infections has been observed; therefore, the objective of this study was to evaluate the clinical characteristics and outcomes of these infections. Methods: We included patients with NTM infections between 2001-2017 and obtained risk factors, clinical features and outcomes; finally, we compared this data between slowly growing (SGM) and rapidly growing mycobacteria (RGM). Results: A total of 230 patients were evaluated, 158 (69%) infected and 72 (31%) colonized/pseudoinfected. The average annual incidence in the first 11 years of the study was 0.5 cases per 1000 admissions and increased to 2.0 cases per 1000 admissions later on. The distribution of NTM infections was as follows: bloodstream and disseminated disease 72 (45%), lung infection 67 (42%), skin and soft tissue infection 19 (12%). Mycobacterium avium complex was the most common isolate within SGM infections, and HIV-infected patients were the most affected. Within RGM infections, M. fortuitum was the most common isolate from patients with underlying conditions such as cancer, type-2 diabetes mellitus, presence of invasive devices, and use of immunosuppressive therapy. We did not find significant differences in deaths and persistent infections between disseminated SGM infection when compared to disseminated RGM infection (42% vs. 24%, p = 0.22). However, disseminated SGM infection required a longer duration of therapy than disseminated RGM infection (median, 210 vs. 42 days, p = 0.01). NTM lung disease showed no significant differences in outcomes among treated versus non-treated patients (p = 0.27). Conclusions: Our results show a significant increase in the number of Non-tuberculosis-mycobacteria infections in our setting. Patients with slow-growing-mycobacteria infections were mainly persons living with human immunodeficiency virus . Older patients with chronic diseases were common among those with rapidly-growing-mycobacteria infections. For non-tuberculosis-mycobacteria lung infection, antibiotic therapy should be carefully individualized.

Clinical and epidemiological characteristics of patients diagnosed with covid-19 in a tertiary care center in Mexico City: a prospective cohort study

ABSTRACT Background: Regional information regarding the characteristics of patients with coronavirus disease (COVID)-19 is needed for a better understanding of the pandemic. Objective: The objective of the study to describe the clinical features of COVID-19 patients diagnosed in a tertiary-care center in Mexico City and to assess differences according to the treatment setting (ambulatory vs. hospital) and to the need of intensive care (IC). Methods: We conducted a prospective cohort, including consecutive patients with COVID-19 from February 26, 2020 to April 11, 2020. Results: We identified 309 patients (140 inpatients and 169 outpatients). The median age was 43 years (interquartile range, 33-54), 59.2% men, and 18.6% healthcare workers (12.3% from our center). The median body mass index (BMI) was 29.00 kg/m2 and 39.6% had obesity. Compared to outpatients, inpatients were older, had comorbidities, cough, and dyspnea more frequently. Twenty-nine (20.7%) inpatients required treatment in the IC unit (ICU). History of diabetes (type 1 or 2) and abdominal pain were more common in ICU patients compared to non-ICU patients. ICU patients had higher BMIs, higher respiratory rates, and lower room-air capillary oxygen saturations. ICU patients showed a more severe inflammatory response as assessed by white blood cell count, neutrophil and platelet count, C-reactive protein, ferritin, procalcitonin, and albumin levels. By the end of the study period, 65 inpatients had been discharged because of improvement, 70 continued hospitalized, and five had died. Conclusions: Patients with comorbidities, either middle-age obese or elderly complaining of fever, cough, or dyspnea, were more likely to be admitted. At admission, patients with diabetes, high BMI, and clinical or laboratory findings consistent with a severe inflammatory state were more likely to require IC.

Enfermedad granulomatosa hepática / Hepatic granulomatous disease

Resumen Los granulomas son lesiones circunscritas compuestas principalmente por células mononucleares que surgen en respuesta a estímulos antigénicos pobremente degradables. Se encuentran en 2 a 15 % de las biopsias hepáticas; su hallazgo puede significar desde un fenómeno incidental, hasta la manifestación de una enfermedad sistémica de origen infeccioso, autoinmune o neoplásico. El cuadro clínico suele apuntar a la patología subyacente, sin embargo, la lista de condiciones asociadas es amplia y difiere con base en los antecedentes epidemiológicos y a las características basales del paciente. El elemento de mayor utilidad para su estudio es la historia clínica exhaustiva, con énfasis en viajes recientes, exposición de riesgo y consumo de fármacos o alimentos crudos o exóticos. El análisis histopatológico detallado puede auxiliar en la identificación de la etiología, por ejemplo, la presencia de granulomas epitelioides con necrosis caseosa indica tuberculosis y su ausencia, sarcoidosis; la abundancia de eosinófilos es señal de reacciones farmacológicas o infecciones parasitarias; la presencia de cuerpos extraños puede ser la causa de la enfermedad granulomatosa hepática. En este artículo describimos los aspectos clínico-patológicos básicos de esta enfermedad y proveemos un breve resumen de las etiologías más comunes, principalmente en la región de Latinoamérica.

Abstract Granulomas are circumscribed lesions mainly composed of mononuclear cells that arise in response to poorly degradable antigenic stimuli. They are found in 2-15 % of liver biopsies and the meaning of their finding can range from an incidental phenomenon to the manifestation of a systemic disease of infectious, autoimmune or neoplastic origin. Clinical presentation usually points at the underlying pathology; however, the list of associated conditions is extensive, and differs based on patient epidemiological history and baseline characteristics. The most useful element for their study is a thorough medical history, with an emphasis on recent trips, exposures and consumption of drugs or raw or exotic foods. Detailed histopathological analysis may help identify the etiology. For example, the presence of epithelioid granulomas with caseous necrosis indicates tuberculosis and, its absence, sarcoidosis; eosinophil abundance can be associated with drug reactions or parasitic infections; and the presence of foreign bodies can be the cause of granulomatous liver disease (GLD). In this article, we describe the basic clinical-pathological aspects of GLD, and provide a brief summary of the most common etiologies, with an emphasis on the Latin-American region.

Mycobacterium tuberculosis complex bacteremia among HIV and non-HIV patients in a Mexican tertiary care center

ABSTRACT Objectives: To determine the factors associated with Mycobacterium tuberculosis complex-positive blood culture. Methods: Case-control study. Sociodemographic, clinical and laboratory data were collected from 2000 to 2015. Results: We reviewed medical records of 533 patients with culture-proven tuberculosis, of whom 27.2% (145/533) had blood culture available. Patients with mycobacteremia presented more frequently with abdominal tuberculosis, body mass index <18 kg/m2, and had lower hemoglobin and albumin levels. No differences were observed regarding HIV status. Conclusions: Few studies have reported on the characteristics associated with Mycobacterium tuberculosis complex bacteremia, especially among Human Immunodeficiency Virus-negative patients. Out of 145 tuberculosis-infected patients with blood culture results available, 21 turned out positive. Anemia, hypoalbuminemia, and a body mass index < 18 kg/m2 were associated with mycobacteremia.

Seroprevalence of brucellosis among dairy farm workers in Mexico / Seroprevalencia de brucelosis entre trabajadores de una cuenca lechera en México

Abstract: Objective: To describe the seroprevalence and associated factors for brucellosis among dairy farm workers. Materials and methods: We performed a secondary analysis of a data set and sera from a previous cross-sectional study in a dairy farm. Sera were tested for Brucella spp. antibodies by the slide agglutination test. Seropositivity was defined as a titer ≥1:40; recent infection was titers ≥1:160. Results: We tested 331 human sera. Seroprevalence of brucellosis was 18.1% (60/331; 95% CI 14.1-22.7); 13.3% of them (8/60; 95% CI 5.9 24.5) corresponded to recent infection. Highexposure occupation (calf caretaker; OR 3.3; 95%CI 1.1 - 9.7), daily hours in contact with cows (OR 1.1; 95%CI 1.03 - 1.2), and living on-site (OR 2.2; 95% CI 1.1 - 4.4) remained independently associated with seropositivity. Conclusions: We found a high seroprevalence of brucellosis among dairy farm workers, as well as a significant association among those with prolonged and close contact with cattle.

Resumen: Objetivos: Describir la seroprevalencia y factores asociados con la brucelosis en los trabajadores de una cuenca lechera. Material y métodos: Se realizó un análisis secundario de datos y sueros obtenidos en una cuenca lechera. Se buscaron anticuerpos contra Brucella spp. en los sueros por medio de la prueba de aglutinación en placa. Se definió seropositividad a partir de un título ≥1:40, e infección reciente con títulos ≥1:160. Resultados: Se analizaron 331 sueros humanos. La seroprevalencia de brucelosis fue de 18.1% (60/331; IC 95% 14.1-22.7); el 13.3% (8/60; IC 95% 5.9 24.5) correspondieron a infección reciente. Alta exposición (becerrero; RM 3.3; IC 95% 1.1 - 9.7), horas diarias en contacto con vacas (RM 1.1; IC 95% 1.03 - 1.2), y vivir en el establo (RM 2.2; IC 95% 1.1 - 4.4) estuvieron asociadas independientemente con seropositividad. Conclusiones: Se encontró alta seroprevalencia de brucelosis en trabajadores de una cuenca lechera, y asociación en aquellos con contacto cercano y prolongado con vacas.

Tuberculosis activa en una cohorte de reclusos infectados por VIH en una cárcel de la Ciudad de México: características clínicas y epidemiológicas / Active tuberculosis in a cohort of HIV-infected inmates in a prison in Mexico City: clinical and epidemiological characteristics

OBJETIVO: Determinar las características clínicas y epidemiológicas de los casos con tuberculosis (TB) activa en población de cárceles con VIH, que se ve especialmente afectada por ambas epidemias. La infección por VIH incrementa significativamente la probabilidad del desarrollo de TB. MATERIAL Y MÉTODOS: Se realizó un estudio de cohorte en sujetos infectados por VIH e internados en un reclusorio de la Ciudad de México. RESULTADOS: Se encontraron 172 pacientes con VIH, 28 con TB activa (16.3%) - 21 (12.2%) con afección pulmonar - con una tasa de incidencia de 7.7 por 100 sujetos/año para TB activa y de 4.7 por 100 sujetos/ año para TB pulmonar. No se encontró drogorresistencia. Dieciocho aislados fueron tipificados por RFLP, con una tasa de transmisión calculada de 11%. CONCLUSIÓN: Se encontró una prevalencia de TB en esta población mil veces superior a la observada en la población general y datos sugerentes de transmisión al interior de la cárcel.

OBJECTIVE: To determine the clinical and epidemiological characteristics of prison inmates with active tuberculosis in HIV-positive prison populations. MATERIALS AND METHODS: We conducted a cohort study in HIV-infected subjects in a prison in Mexico City, with the aim of determining clinical and epidemiological characteristics of cases with active TB. RESULTS: We detected 172 HIV infected inmates and TB in 28 of them (16.3%) - 21 (12.2) with pulmonary TB - with an incidence rate of 7.7/100 persons/year for active TB and 4.7/100 persons/year for pulmonary TB. No drug resistance was found. Two clusters (4 and 2 subjects) were observed after RFLP-typing of 18 isolates, with a transmission rate of 11% by molecular and clinical analysis. CONCLUSIONS: The prevalence of active TB was found to be a thousand times greater than in the general population. Evidence of transmission inside the prison was also found.

Increasing prevalence of extended-spectrum-betalactamase among Gram-negative bacilli in Latin America: 2008 update from the Study for Monitoring Antimicrobial Resistance Trends (SMART)

OBJECTIVES: This analysis of the Study for Monitoring Antimicrobial Resistance Trends (SMART) evaluated the susceptibility patterns of Enterobacteriaceae in Latin America in 2008, with emphasis on susceptibility trends of E. coli and K. pneumoniae. METHODS: Clinical isolates were recovered from intra-abdominal infections (IAI) from 23 centers in 10 Latin American countries. Isolates were sent to a central laboratory for confirmation of identification, antimicrobial susceptibility and ESBL testing, following the Clinical Laboratory Standards Institute (CLSI) guidelines. RESULTS: Of 1,003 Gram-negative bacilli collected from intra-abdominal infections, E. coli and K. pneumoniae were the most commonly isolated organisms, and 26.8 percent of E. coli and 37.7 percent of K. pneumoniae were ESBL positive. Ertapenem and imipenem were the most consistently active agents tested; 99 percent of ESBLpositive E. coli isolates were susceptible to ertapenem and 100 percent to imipenem as well, and 91 percent of ESBL-positive K. pneumoniae were susceptible to ertapenem and 98 percent to imipenem. Quinolones and cephalosporins were less active, achieving 1.5 percent to 76 percent inhibition against ESBL-producing E. coli and 3.5 percent to 61 percent inhibition against K. pneumoniae. CONCLUSIONS: Local and unit-specific surveillance data is particularly important for selection of empiric therapy and in community-acquired infections as they can help the clinician with antibiotic selection by providing guidance regarding the likely pathogens and their resistance profiles. Our data also confirm the increasing frequency with which ESBL-producing organisms are found in the community setting, with 31.4 percent of communityacquired and 24.9 percent of hospital-acquired infections found to produce ESBLs. Imipenem and ertapenem are the most active agents tested for ESBL-positive E. coli and K. pneumoniae.

Consenso para el diagnóstico clínico y microbiológico y la prevención de la infección por Bordetella pertussis / Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention

La tos ferina sigue siendo responsable de una carga de enfermedad importante en el mundo. Aunque la implementación del uso de la vacuna contra esta enfermedad ha disminuido en gran medida el número de casos en la población pediátrica, se ha observado que la inmunidad inducida por la vacuna y por la infeccion natural disminuye con el tiempo lo que hace nuevamente susceptibles a adolescentes y adultos jóvenes que pueden transmitir la enfermedad a lactantes no inmunizados o con esquema de vacunación incompleto. Este documento, resultado de la reunión de un grupo internacional de expertos en la Ciudad de México, ha analizado la información médica reciente para establecer el estado actual de la epidemiología, diagnóstico, vigilancia y, especialmente, el valor de la dosis de refuerzo con dTpa en adolescentes y adultos como estrategia de prevención de tos ferina en México.

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.

Genotyping of the MTL loci and susceptibility to two antifungal agents of Candida glabrata clinical isolates

The opportunistic fungal pathogen Candida glabrata is the second most common isolate from bloodstream infections worldwide and is naturally less susceptible to the antifungal drug fluconazole than other Candida species. C. glabrata is a haploid yeast that contains three mating-type like loci (MTL), although no sexual cycle has been described. Strains containing both types of mating information at the MTL1 locus are found in clinical isolates, but it is thought that strains containing type a information are more common. Here we investigated if a particular combination of mating type information at each MTLlocus is more prevalent in clinical isolates from hospitalized patients in Mexico and if there is a correlation between mating information and resistance to fluconazole and 5-fluorocytosine. We found that while both types of information at MTL1 are equally represented in a collection of 64 clinical isolates, the vast majority of isolates contain a-type information at MTL2 and α-type at MTL3. We also found no correlation of the particular combination of mating type information at the three MTL loci and resistance to fluconazole.

Enfermedad asociada a Clostridium difficile en América Latina / Clostridum difficile associated disease in Latin America

La enfermedad asociada a Clostridium difficile (EACD) se ha incrementado de manera sostenida en todo el mundo durante los últimos 10 años. Sin embargo, son pocos los estudios en América Latina que abordan el tema. En una revisión bibliográfica en las bases de datos documentales de los países latinoamericanos, encontramos solo siete artículos recientes en los cuales se describen las características clínicas, los factores de riesgo y, en algunos, el desenlace de la infección. De estos artículos solo uno fue prospectivo, mientras que los restantes fueron retrospectivos, transversales o de casos y controles. Esta revisión estuvo orientada fundamentalmente hacia la población adulta en hospitalización, aunque la edad de los pacientes va de los 13 años en algunos trabajos. En dos análisis recientes se realizó cultivo celular para determinar efecto citopático y en el resto la determinación fue por inmunoensayo. En todos, el empleo de antibióticos (fluoroquinolonas, clindamicina y cefalosporinas) tuvo asociación con la EACD, y el tratamiento de la enfermedad incluyó casi siempre metronidazol por vía oral; únicamente en un centro se utilizó vancomicina. La mortalidad atribuible fue menor (4%) a la informada en países desarrollados. Dado que en América Latina existen escasas investigaciones de EACD con pocos pacientes y casi todas retrospectivas, se percibió la necesidad de determinar la frecuencia de esta enfermedad, conocer mejor los factores de riesgo y las verdaderas tasas de mortalidad global y atribuible.

Clostridium difficile associated disease (CDAD) has shown a sustained increase worldwide over the last ten years. However, there are few studies on this topic in Latin America. We conducted a comprehensive literature review using medical databases of Latin American countries. We found only seven recent papers in which clinical characteristics and risk factors were analyzed; some included outcome variables. Of these articles, only one was prospective, while the rest were either retrospective, cross-sectional or case-control studies. Most studies were done among hospitalized adult patients, even though patients 13+ years were also included in some reports. Only two recent clinical studies used cell culture to determine a cytopathic effect and the rest included immunoenzymatic assays. In general, all the studies we reviewed showed that the use of fluorquinolones, clindamycin, and cephalosporins were the antibiotics mostly associated with CDAD. Treatment schedules generally included metronidazol, although vancomycin was reported in one. Attributable mortality was lower than the mortality described in previous reports from hospitals in developed countries. Studies where this outcome was included did not surpass 4%, a significant difference from the findings from developed countries. In Latin America there are few studies that describe this clinical problem, they generally include small sample sizes and most are retrospective. There is a clear need to design and carry out prospective studies that will allow us to determine the true prevalence of this health problem

Investigación sobre epidemiología convencional y molecular de tuberculosis en Orizaba, Veracruz, 1995-2008 / Research on conventional and molecular epidemiology of tuberculosis in Orizaba, Veracruz, 1995-2008

Se describen los resultados de investigación del Consorcio Mexicano contra la Tuberculosis, en la Jurisdicción Sanitaria de Orizaba, Veracruz, entre 1995 y 2008. Las aportaciones principales de los trabajos se refieren a los siguientes rubros: 1. Epidemiología convencional y molecular (medición de la carga de la enfermedad, tendencias, factores de riesgo y grupos vulnerables; descripción de las consecuencias de la farmacorresistencia e identificación de factores que favorecen la transmisión en la comunidad y en los hospitales). 2. Desarrollo de técnicas rápidas para conservación de muestras respiratorias que permitan el aislamiento y diagnóstico de farmacorresistencia de M. tuberculosis en campo. 3. Evaluación de la prueba tuberculínica, respuesta inmunológica al Bacilo de Calmette-Guerin (BCG), biomarcadores de la respuesta inmunitaria y medidas de control. 4. Comentarios en torno a aspectos éticos de la investigación en tuberculosis. Además se describe el impacto en políticas públicas, la transferencia de tecnología, la formación de recursos humanos y las perspectivas a futuro.

This study describes the achievements of the Mexican Consortium against Tuberculosis, in the Sanitary District of Orizaba, Veracruz, Mexico between 1995 and 2008. In brief, the main results can be classified as follows: 1) Conventional and molecular epidemiology (measurement of burden of disease, trends, risk factors and vulnerable groups, consequences of drug resistance, identification of factors that favor nosocomial and community transmission); 2) Development of diagnostic techniques to detect drug resistance, description of circulating clones and adaptation of simple techniques to be used in the field; 3) Evaluation of usefulness of tuberculin skin test, immunologic responses to BCG, impact of directly observed therapy for tuberculosis (DOTS), and study of immunological biomarkers and 4) Comments on ethical aspects of tuberculosis research. Additionally, we describe the impact on public policies, transference of technology, capacity building and future perspectives.

Infecciones oportunistas en el síndrome de inmunodeficiencia adquirida: La historia en México a 20 años del inicio de la epidemia / Opportunistic infections in the acquired inmunodeficiency syndrome: the history in Mexico 20 years after the begining of the epidemic

Las infecciones oportunistas (IO's) complican la evolución de los pacientes VIH-positivos. Se han observado diferencias regionales en la incidencia y en la prevalencia de las IO's en los pacientes con SIDA en relación con deficiencias inmunológicas, factores ambientales y a las condiciones socioeconómicas y sanitarias en el entorno de estos pacientes. Al inicio de la epidemia, la incidencia global de IO's alcanzó entre 60 y 100% de los pacientes VIH-positivos. Posteriormente, la incidencia de tuberculosis, de enteropatógenos, de Pneumocystis jiroveci y de Mycobacterium avium ha disminuido en el hemisferio occidental debido a la profilaxis farmacológica, a la mejoría en la atención médica y a la introducción de la terapia antirretroviral. Este fenómeno ha sido más obvio en Estados Unidos, en Europa occidental y en la mayoría de los países de América Latina. Al inicio de la epidemia de VIH, la frecuencia de las diferentes IO's en México fue similar en todos los reportes clínicos, la mayoría de los casos mostraban candidiasis mucocutánea o esofágica seguida por neumonía por P. jiroveci y enteritis por Cryptosporidium sp. Recientemente, se ha observado un incremento en el número de episodios de retinitis por CMV y de infección diseminada por M. avium como consecuencia de la sobrevida más prolongada de los pacientes VIH-positivos. En conclusión, las tasas de morbilidad y de mortalidad en los pacientes VIH-positivos han disminuido como resultado de la mejoría de la atención en el cuidado de estos pacientes, la aplicación de medidas de prevención específicas para IO's y más recientemente por la introducción de terapia antirretroviral muy activa.

Opportunistic infections (OI's) complicate the outcome of HIV-positive patients. There have been observed regional differences in the incidence and the prevalence of OI's in AIDS patients secondary to immunological deficiencies, environmental factors and socioeconomic and sanitary conditions. At the beginning of the epidemic, the global incidence of OI's in HIV-positive patients was between 60 and 100%. Later, the incidence of tuberculosis, intestinal pathogens, Pneumocystis jiroveci and Mycobacterium avium has decreased in the western hemisphere, because of the pharmacological prophylaxis, the improvement in the medical care and the introduction of the antiretroviral therapy. This phenomenon has been more evident in the United States, in Western Europe, and most Latin American countries. At the beginning of the HIV epidemic, the frequency of the different OI's in Mexico was similar among all the clinical reports; the majority of the cases showed mucocutaneous or esofagic candidiasis, followed by P. jiroveci pneumonia, and Cryptosporidium sp. enteritis. Recently, we have seen an increased in the number of episodes of CMV retinitis and M. avium disseminated infection as evidence of a prolonged survival of the HIV-positive patients. In conclusion, the morbidity and mortality rates in the HIV-positive patients have diminished as a result of the improvement of the medical care, the application of specific IO's prevention measures and more recently to the introduction of HAART. KEY WORDS. AIDS. HAART. Pneumocystis jiroveci. Mycobacterium avium. Toxoplasma gondii. Opportunistic infections.