Differential activation of innate and adaptive lymphocytes during latent or active infection with Mycobacterium tuberculosis.

Most individuals infected with Mycobacterium tuberculosis (Mtb) have latent tuberculosis (TB), which can be diagnosed with tests (such as the QuantiFERON-TB Gold test [QFT]) that detect the production of IFN-γ by memory T cells in response to the Mtb-specific antigens 6 kDa early secretory antigenic target EsxA (Rv3875) (ESAT-6), 10 kDa culture filtrate antigen EsxB (Rv3874) (CFP-10), and Mtb antigen of 7.7 kDa (Rv2654c) (TB7.7). However, the immunological mechanisms that determine if an individual will develop latent or active TB remain incompletely understood. Here we compared the response of innate and adaptive peripheral blood lymphocytes from healthy individuals without Mtb infection (QFT negative) and from individuals with latent (QFT positive) or active TB infection, to determine the characteristics of these cells that correlate with each condition. In active TB patients, the levels of IFN-γ that were produced in response to Mtb-specific antigens had high positive correlations with IL-1ß, TNF-α, MCP-1, IL-6, IL-12p70, and IL-23, while the proinflammatory cytokines had high positive correlations between themselves and with IL-12p70 and IL-23. These correlations were not observed in QFT-negative or QFT-positive healthy volunteers. Activation with Mtb-soluble extract (a mixture of Mtb antigens and pathogen-associated molecular patterns [PAMPs]) increased the percentage of IFN-γ-/IL-17-producing NK cells and of IL-17-producing innate lymphoid cell 3 (ILC3) in the peripheral blood of active TB patients, but not of QFT-negative or QFT-positive healthy volunteers. Thus, active TB patients have both adaptive and innate lymphocyte subsets that produce characteristic cytokine profiles in response to Mtb-specific antigens or PAMPs. These profiles are not observed in uninfected individuals or in individuals with latent TB, suggesting that they are a response to active TB infection.

Pulmonary Histoplasmosis in a Referral Hospital in Mexico City.

Pulmonary histoplasmosis is caused by inhaling Histoplasma capsulatum. Less than 1% develops the disease. Risk factors in immunocompetent individuals are environmental exposures in endemic areas. The objective of this study is to determine the frequency, clinical, and microbiological characteristics in immunocompetent patients. A retrospective case series study of patients diagnosed with pulmonary histoplasmosis was performed in a respiratory care unit in Mexico City from 2000 to 2020. Each patient had bronchial lavage, and three patients underwent thoracoscopy for the lung tissue sample taken for the culture in Sabouraud Dextrose Agar. Twelve patients were identified, 8 males and 4 females; the predominant symptoms were fever (83%), dyspnea (75%), chest pain (66%), hemoptysis (41%), and weight loss (33%). The computed tomography of the chest showed the following findings: patchy consolidation 12 (100%), hilar adenopathy 6 (50%), pleural effusion 6 (50%), caverns 3 (25%), and solitary pulmonary nodule in one patient (8%). Histoplasma capsulatum was found in the culture of all twelve patients. The signs and symptoms of the disease are mediated by the immune status of the host. The clinical picture is often confused with systemic diseases. It is important to have a high degree of clinical suspicion to make a timely diagnosis.

Identificación de un brote de SARSCoV-2 (Covid-19) en un centro gerontológico de la Ciudad de México.

OBJECTIVE: To describe a Covid-19 outbreak in a gerontological center in Mexico City. MATERIAL AND METHODS: Cross-sectional study in older adults. The association of risk factors for dying from Covid-19 was analyzed using a multiple logistic regression model. RESULTS: One hundred and two elders with an average age of 82.5 ± 8.8 years were included. Fifty-five (54%) tested positive and 47 (46%) were negative for the new coronavirus. Using the multiple logistic regression model, people with frailty had an OR of 11.6 of dying from Covid-19 compared to robust people (p-value = 0.024). CONCLUSION: The Covid-19 outbreak was initially caused by a resident of the center and spread by cross infection. In vulnerable populations, early detection, isolation, and follow-up of contacts should be carried out, as well as the identification of risk factors in order to reduce the spread and mortality caused by SARSCoV-2.

Characteristics and mortality of Mexican patients with COVID-19 and mechanical ventilation.

INTRODUCTION: COVID-19-associated mortality in patients who require mechanical ventilation is unknown in the Mexican population. OBJECTIVE: To describe the characteristics of Mexican patients with COVID-19 who required mechanical ventilation. METHODS: Observational cohort study carried out in an intensive care unit from March 25 to July 17, 2020. Data were obtained from a prospective database and electronic medical records, and were analyzed with the chi-square test, Fisher's exact test or Mann-Whitney's U-test. RESULTS: One hundred patients required mechanical ventilation; median age was 56 years, 31 % were females and 97 % were Latin American. Most common comorbidities were obesity (36 %), diabetes (26 %), hypertension (20 %), and chronic or end-stage kidney disease (10 %). At the end of the analysis, 11 patients remained in the ICU, 31 had been discharged alive and 58 (65.2 %) died; survivors were younger, had lower scores on severity and organ dysfunction scales, lower levels of C-reactive protein at ICU admission, were less likely to receive hemodialysis and vasopressors, and had longer hospital and ICU stays. CONCLUSIONS: This study adds information on the presentation and results of SARS-CoV-2-infected patients who require mechanical ventilation.

INTRODUCCIÓN: La mortalidad por COVID-19 en quienes requieren ventilación mecánica se desconoce en la población mexicana. OBJETIVO: Describir las características de pacientes mexicanos con COVID-19 que requirieron ventilación mecánica. MÉTODOS: Estudio de cohorte observacional en una unidad de terapia intensiva, del 25 de marzo al 17 de julio de 2020. Los datos se obtuvieron de una base de datos prospectiva y de registros clínicos electrónicos; fueron analizados con c2, prueba exacta de Fisher o prueba U de Mann-Whitney. RESULTADOS: Cien pacientes recibieron ventilación mecánica, la edad media fue de 56 años, 31 % era del sexo femenino y 97 %, latinoamericano. Las comorbilidades más comunes fueron obesidad (36 %), diabetes (26 %), hipertensión (20 %) y enfermedad renal crónica o renal terminal (10 %). Al término del análisis, 11 pacientes permanecían en la UCI, 31 egresaron vivos y 58 (65.2 %) fallecieron; los sobrevivientes fueron más jóvenes, con menores puntuación en las escalas de gravedad y disfunción orgánica, menores niveles de proteína C reactiva al ingreso a la UCI, menor propensión a hemodiálisis, necesidad de, necesidad de vasopresores y con mayor estancia hospitalaria y en la UCI. CONCLUSIONES: Este estudio agrega información sobre la presentación y resultados de pacientes con ventilación mecánica infectados con SARS-CoV-2.

Impact of strategic planning, organizational culture imprint and care bundles to reduce adverse events in the ICU.

OBJECTIVE: To evaluate the occurrence of adverse events during a multifaceted program implementation. DESIGN: Cross-sectional secondary analysis. SETTING: The respiratory-ICU of a large tertiary care center. PARTICIPANTS: Retrospectively collected data of patients admitted from 1 March 2010 to 28 February 2014 (usual care period) and from 1 March 2014 to 1 March 2017 (multifaceted program period) were used. INTERVENTIONS: The program integrated three components: (1) strategic planning and organizational culture imprint; (2) training and practice and (3) implementation of care bundles. Strategic planning redefined the respiratory-ICU Mission and Vision, its SWOT matrix (strengths, weaknesses, opportunities, threats) as well as its medium to long-term aims and planned actions. A 'Wear the Institution's T-shirt' monthly conference was given in order to foster organizational culture in healthcare personnel. Training was conducted on hand hygiene and projects 'Pneumonia Zero' and 'Bacteremia Zero'. Finally, actions of both projects were implemented. MAIN OUTCOME MEASURES: Rates of adverse events (episodes per 1000 patient/days). RESULTS: Out of 1662 patients (usual care, n = 981; multifaceted program, n = 681) there was a statistically significant reduction during the multifaceted program in episodes of accidental extubation ([Rate ratio, 95% CI] 0.31, 0.17-0.55), pneumothorax (0.48, 0.26-0.87), change of endotracheal tube (0.17, 0.07-0.44), atelectasis (0.37, 0.20-0.68) and death in the ICU (0.82, 0.69-0.97). CONCLUSIONS: A multifaceted program including strategic planning, organizational culture imprint and care protocols was associated with a significant reduction of adverse events in the respiratory-ICU.

Identificación de Mycobacterium bovis en pacientes con diagnóstico de tuberculosis pulmonar y extrapulmonar.

INTRODUCTION: In Mexico, there is an alarming increase in the number of cases of Mycobacterium bovis infection on pulmonary and extrapulmonary presentations. The lack of timely identification triggers complications and increases mortality. OBJECTIVE: To know the frequency of M. bovis infections in clinical samples of patients with tuberculosis in the mycobacteria laboratory of a reference hospital in Mexico City. METHOD: Prospective, descriptive study. Strains isolated from biological material were studied in Löwestein-Jensen and MGITI960 cultures. M. bovis was identified by amplifying the RD9 fragment with end-point polymerase chain reaction (PCR). RESULTS: Eight-hundred and fifty tuberculosis-diagnosed patients were included; in 441 cases, Mycobacterium tuberculosis was confirmed by positive culture (250 pulmonary, 65 ganglionic, 39 renal, 34 meningeal, 25 miliary, 14 pleural, 8 peritoneal, 4 bone and 2 pericardial cases). Forty-eight strains (10.8%) were typified as M. bovis by amplification of the RD9 fragment with end-point PCR. CONCLUSIONS: M. bovis is not currently thought of a causative agent of tuberculosis, which could be the cause of pharmacological treatment failure. In this study, the main extrapulmonary form was observed to be cervical lymphadenopathy.

INTRODUCCIÓN: En México existe un incremento alarmante de casos de infección pulmonar y extrapulmonar por Mycobacterium bovis. La falta de identificación oportuna deriva en complicaciones y eleva la mortalidad. OBJETIVO: Conocer la frecuencia de infecciones por Mycobacterium bovis en muestras clínicas de pacientes con tuberculosis, identificadas en el laboratorio de micobacterias en un hospital de concentración de la Ciudad de México. MÉTODO: Estudio prospectivo, descriptivo. Se estudiaron cepas aisladas de material biológico en cultivos Löwestein-Jensen y MGITI960. La identificación de Mycobacterium bovis se realizó mediante la amplificación del fragmento RD9 por PCR punto final. RESULTADOS: Se incluyeron 850 pacientes con diagnóstico de tuberculosis, en 441 casos se confirmó Mycobacterium tuberculosis por cultivo positivo (250 casos pulmonares, 65 ganglionares, 39 renales, 34 meníngeos, 25 miliares, 14 pleurales, ocho peritoneales, cuatro óseos y dos pericárdicos). Se tipificaron 48 cepas (10.8 %) como Mycobacterium bovis por amplificación del fragmento RD9 por PCR punto final. CONCLUSIONES: Actualmente no se piensa en Mycobacterium bovis como agente causal de tuberculosis, lo que pudiera ser la causa del fracaso del tratamiento farmacológico. En este estudio se observó que la principal forma extrapulmonar es la linfadenopatía cervical.

Tuberculosis extrapulmonar: un problema de salud pública.

Extrapulmonary tuberculosis is defined as that case of tuberculosis clinically diagnosed and confirmed by bacteriological studies that affects tissues and organs outside the lung parenchyma. Mexico is in third place among Latin American countries in terms of the incidence of pulmonary and extrapulmonary tuberculosis. Culture methods are still the gold standard for the diagnosis of extrapulmonary tuberculosis since they identify the species and susceptibility to drugs.

La tuberculosis extrapulmonar es aquella tuberculosis diagnosticada clínicamente y confirmada por estudios bacteriológicos que afecta a tejidos y órganos fuera del parénquima pulmonar. México es el tercer lugar en América Latina en incidencia de tuberculosis pulmonar y extrapulmonar. Los métodos de cultivo siguen siendo el método de referencia para el diagnóstico de tuberculosis extrapulmonar, ya que identifican la especie y la sensibilidad a los fármacos.

Burnout symptoms among physicians and nurses before, during and after COVID-19 care. / Síntomas de Burnout entre médicos y enfermeros antes, durante y después de atender pacientes con COVID-19.

OBJECTIVE: this study evaluated burnout symptoms among physicians and nurses before, during and after COVID-19 care. METHOD: a cross-sectional comparative study in the Pulmonary Care unit of a tertiary-level public hospital. The Maslach Burnout Inventory was used. RESULTS: 280 surveys were distributed across three periods: before (n=80), during (n=105) and after (n=95) COVID-19 care; 172 surveys were returned. The response rates were 57.5%, 64.8% and 61.1%, respectively. The prevalence of severe burnout was 30.4%, 63.2% and 34.5% before, during and after COVID-19 care (p<0.001). Emotional exhaustion (p<0.001) and depersonalization (p=0.002) symptoms were more prevalent among nurses than among physicians. Severe burnout was more prevalent in women, nurses and night shift staff. CONCLUSION: the high prevalence of burnout doubled in the first peak of hospital admissions and returned to pre-pandemic levels one month after COVID-19 care ended. Burnout varied by gender, shift and occupation, with nurses among the most vulnerable groups. Focus on early assessment and mitigation strategies are required to support nurses not only during crisis but permanently.

The Prevalence of Depression and Anxiety Symptoms and Their Association With Respiratory Diseases.

INTRODUCTION: Patients with respiratory diseases face adverse situations such as symptom management, general condition deterioration, and a hostile perception of the hospital environment, favoring the appearance of anxiety and depression. METHODS: A total of 317 patients hospitalized for a disease of pulmonary origin were analyzed and divided into the following subgroups: infectious, oncological, acute, and chronic diseases. Patients over 18 years of age with preserved cognitive capacity were included in the study. The Hospital Anxiety and Depression Scale (HADS) was applied to them on the second or fourth day of their hospital stay and five days after the first evaluation. Multiple linear regression models were carried out to analyze the association between anxiety and depression measured over two different periods. The models present the statistically significant variables with a 95% confidence level. RESULTS: The patients presented with anxiety in 74.4% of cases, mainly those with acute respiratory diseases (42.4%) and neoplastic diseases (27.5%). A total of 69.5% presented with depression, with symptoms more significant in those with chronic and oncological pulmonary diseases and those with no job. Patients with at least one comorbidity presented with anxiety in 53.9% of cases and depression in 52.1% of cases. Linear regression models were carried out and showed that anxiety was 1.75 and 1.84 times more frequent in patients with chronic diseases compared to those with infectious pathologies in the first and second reviews, respectively. The linear regression model also showed a higher frequency of depressive symptoms in patients with chronic conditions (1.62 times) compared to the group with infectious and contagious pathologies, and prolonged hospital stays were associated with depressive symptoms 1.37 times more than short stays. CONCLUSIONS: Anxiety and depression are frequent disorders in patients with respiratory diseases, negatively affecting the prognosis. Routine mental health screening and multidisciplinary management are essential in this population.

Necrotizing pneumonia due to Saprochaete capitata in a patient with diabetes mellitus. Case report.

Saprochaete capitata is a yeast-like fungus of the Dipodascaceae family, capable of colonizing the skin and the respiratory and gastrointestinal tracts. We present a 56-year-old man with diabetes mellitus who was admitted to the hospital presenting with fever, cough and hemoptysis. The diagnosis of necrotizing pneumonia was made by direct microscopy of the bronchoalveolar lavage fluid showed and Saprochaete capitata was identified by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight (MALDI-TOF MS®). Treatment consisted of itraconazole 200 mg every 12 hours orally for 30 days, leading to clinical and radiological improvement. Saprochaete capitata infection is a rare cause of pulmonary mycoses.

Pulmonary aspergilloma in immunocompromised patients in a Respiratory Care Unit.

INTRODUCTION: Pulmonary aspergilloma is commonly associated with comorbidities that cause immunodeficiency such as diabetes mellitus, tuberculosis, human immunodeficiency virus/acquired immunodeficiency syndrome and/or a pre-existing parenchymal lung disease such as chronic obstructive pulmonary disease. Predisposing factors can further increase the risk of acquiring this mycosis. Our objective was to determine the frequency, clinical and microbiological characteristics of pulmonary aspergilloma in immunocompromised patients. METHODOLOGY: Retrospective case series of patients diagnosed with pulmonary aspergilloma in a respiratory care unit in Mexico City from 2000 to 2019 was studied. Bronchoalveolar lavage cultures on Sabouraud-dextrose agar and serum galactomannan determination were performed on each patient. RESULTS: We identified twenty-four patients with pulmonary aspergilloma (sixteen male and eight female), thirteen had a history of tuberculosis (54%), seven of diabetes mellitus (29%), three of human immunodeficiency virus/acquired immunodeficiency syndrome (13%) and one of chronic obstructive pulmonary disease (4%). The most commonly reported symptoms were hemoptysis in eighteen patients (75%), dyspnea in sixteen patients (67%) and chest pain in thirteen patients (54%). Aspergillus fumigatus was identified in all cultures and galactomannan was positive in 21 serum samples (87%). CONCLUSIONS: Coexistence of diseases that could suppress the immune system predispose to pulmonary aspergilloma; clinical presentation is often confused with other systemic diseases. A high degree of clinical suspicion is important for early detection.

IL-6, IL-10, sFas, granulysin and indicators of intestinal permeability as early biomarkers for a fatal outcome in COVID-19.

The clinical presentation of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ranges between mild respiratory symptoms and a severe disease that shares many of the features of sepsis. Sepsis is a deregulated response to infection that causes life-threatening organ failure. During sepsis, the intestinal epithelial cells are affected, causing an increase in intestinal permeability and allowing microbial translocation from the intestine to the circulation, which exacerbates the inflammatory response. Here we studied patients with moderate, severe and critical COVID-19 by measuring a panel of molecules representative of the innate and adaptive immune responses to SARS-CoV-2, which also reflect the presence of systemic inflammation and the state of the intestinal barrier. We found that non-surviving COVID-19 patients had higher levels of low-affinity anti-RBD IgA antibodies than surviving patients, which may be a response to increased microbial translocation. We identified sFas and granulysin, in addition to IL-6 and IL-10, as possible early biomarkers with high sensitivity (>73 %) and specificity (>51 %) to discriminate between surviving and non-surviving COVID-19 patients. Finally, we found that the microbial metabolite d-lactate and the tight junction regulator zonulin were increased in the serum of patients with severe COVID-19 and in COVID-19 patients with secondary infections, suggesting that increased intestinal permeability may be a source of secondary infections in these patients. COVID-19 patients with secondary infections had higher disease severity and mortality than patients without these infections, indicating that intestinal permeability markers could provide complementary information to the serum cytokines for the early identification of COVID-19 patients with a high risk of a fatal outcome.

Sera from patients with tuberculosis increase the phagocytic-microbicidal activity of human neutrophils, and ESAT-6 is implicated in the phenomenon.

Background: It has been reported that sera from patients with active pulmonary tuberculosis (APT) induced nuclear changes in normal neutrophils that included pyknosis, swelling, apoptosis, and production of extracellular traps (NETs). Similar changes were observed with some sera from their household contacts but not with sera from healthy, unrelated individuals. It was suggested that those sera from household contacts that induced neutrophil nuclear changes might correspond to people with subclinical tuberculosis. Thus, our experimental approach might serve to identify individuals with early, ongoing disease. Methods: Nuclear changes in neutrophils were fully evident by 3 h of contact and beyond. Circulating mycobacterial antigens were the most likely candidates for this effect. We wanted to know whether the nuclear changes induced on neutrophils by the sera of APT patients would negatively affect the phagocytic/microbicidal ability of neutrophils exposed to APT sera for short periods. Results: We now provide evidence that short-term contact (30 min) with sera from patients with pulmonary tuberculosis increases several phagocytic parameters of normal neutrophils, including endocytosis, myeloperoxidase levels, production of free reactive oxygen species, phagolysosome fusion, and microbicidal activity on Staphylococcus aureus, with these effects not being observed with sera from healthy donors. We also give evidence that suggests that ESAT-6 and CFP-10 are involved in the phenomenon. Conclusion: We conclude that activation is a stage that precedes lethal nuclear changes in neutrophils and suggests that autologous neutrophils must circulate in an altered state in the APT patients, thus contributing to the pathology of the disease.

[A brief review of respiratory diseases in pre-Hispanic times in Mexico]. / Una breve mirada a las enfermedades respiratorias en la época prehispánica en México.

It is known that, in ancient Mexico, diseases of the respiratory system were a major cause of death in the population. Severe epidemics in the XVI Century ravaged and killed nine out of ten indigenous persons. Pre-Hispanic physicians served as medical sorcerers and dealt with the physical and spiritual diseases that afflicted the population. Important medical knowledge pertaining to each culture has been identified; this knowledge explained the diseases depending on the religious beliefs of each culture, and it tried to solve the health problems that afflicted the population at that time.

En el México antiguo se tiene conocimiento de enfermedades propias del sistema respiratorio que fueron una causa importante de mortalidad en la población. Severas epidemias en el siglo XVI asolaron y produjeron la muerte a nueve de cada 10 indígenas. Los médicos prehispánicos se desempeñaban como médicos-hechiceros y atendían las enfermedades físicas y espirituales que aquejaban a la población. Se ha identificado un conocimiento médico importante propio de cada cultura, que explicaba las enfermedades dependiendo de las creencias religiosas e intentaba resolver los problemas de salud que aquejaban a la población en esa época.

[Pulmonary mycosis in patients with diabetes mellitus. Clinical characteristics and risk factors]. / Micosis pulmonares en pacientes con diabetes mellitus. Características clínicas y factores de riesgo.

BACKGROUND: Diabetes mellitus is a public health problem in Mexico, and the trend of the disease is increasing. From 2000 to 2017, 7.32 million new cases were diagnosed, with pulmonary mycoses being one of the most serious complications. AIMS: To describe the frequency and the clinical characteristics of patients diagnosed with pulmonary mycoses, and to identify the risk factors associated with this entity. METHODS: Case-control study, paired by gender (1:1-3) and age (± 5 years), that analyzed patients with pulmonary mycosis (mucormycosis, histoplasmosis, coccidioidomycosis, blastomycosis, aspergillosis, cryptococcosis, paracoccidioidomycosis) and studied the risk factors present in each patient. RESULTS: From the 162 patients studied, 56 suffered pulmonary mycosis and 106 were controls. The median of the age was 51 and 50 years for the cases and for the controls, respectively. Multiple logistic regression analysis showed that patients with diabetes mellitus had an odds ratio of 8,3 (p < 0.001), and patients with a history of tuberculosis had an odds ratio of 8,8 (p < 0.001). CONCLUSIONS: Our results show that 52% of the patients with pulmonary mycoses had a history of diabetes mellitus. Diabetes mellitus is a relevant risk factor for pulmonary mycoses, which are usually diagnosed in advanced stages and have a high mortality.

Comparative analysis of antibodies and lymphocytes in pulmonary tuberculosis patients with negative and positive cultures.

INTRODUCTION: The sputum smear or the culture are the definitive diagnosis of pulmonary tuberculosis. Only a fraction of clinical patients are culture-confirmed. METHODOLOGY: A total of 24 clinical cases (40 ± 14 years old) with positive smear and negative co-morbidity were studied. Cases were selected from 600 patients who attended the pneumology service over two years. A sputum sample was cultured in Löwenstein-Jensen medium with consequent amplification of the rrnA V2 promoter, the differentiation region 4, and the IS6110 insertion sequence of Mycobacterium tuberculosis. After the culture result, the patients were divided into negative (n = 14) or positive (n = 10) culture groups. In addition, 30 samples from healthy donors (45 ± 10 years) were studied. The numbers of CD4, CD8 and CD19 lymphocytes were determined by flow cytometry. Levels of IgA and IgG to M. tuberculosis were measured by ELISA. RESULTS: IgG and IgA levels were detected in patients with positive culture, while only IgA was found in patients with negative cultures. The lymphocyte populations in the two groups were similar.  The presence of a pleural apical cap was found more frequently in patients with negative- (57%) than with positive cultures (10%). CONCLUSIONS: The isotype profile in patients with positive cultures was both IgA and IgG positive, while in patients with negative culture, only IgA was found. The results will contribute to improve the diagnostic algorithm and appropriate treatment of patients with clinical tuberculosis. Further studies are needed to determine if this profile is predictive of the outcome of isolation.

Nontuberculous mycobacteria in cervical lymphadenopathies of HIV positive and HIV-negative adults / Micobacterias no tuberculosas en linfadenopatías cervicales de adultos VIH positivos y VIH negativos

Background: Tuberculosis is a global public health problem, especially in emerging countries. Mycobacterium tuberculosis is the main cause of cervical lymphadenopathy; nontuberculous mycobacteria are relatively common in children and rare in adults. Objective: To identify and establish the frequency of infectious etiology by nontuberculous mycobacteria in Mexican adult patients with cervical lymphadenopathy. Methods: The study included 85 patients over 18 years with cervical lymphadenopathy; 45 were HIV-positive, 40 were HIV-negative; they had no history of tuberculosis treatment and were selected from a third-level hospital. It was carried out a biopsy of the lymph node for the histopathological study, a search for acid-fast bacilli, a tube culture to indicate growth of Mycobacterium BACTEC (MGIT-960) and identification of mycobacterial strain by PCR-RFLP (restriction fragment length polymorfism) of hsp65. Results: In 42 HIV-positive patients (93%), strains corresponded to Mycobacterium tuberculosis complex, two (4.4%) to M. intracellulare and one (2.2%) to M. gordonae. Among HIV-negative patients, 39 of strains (97.5%) corresponded to patients with M. tuberculosis complex and one strain (2.5%) to M. fortuitum. Conclusion: The presence of nontuberculous mycobacteria was found in 4.7% of all cases. Despite this low frequency, it must be taken into account as a possible cause of lymphadenopathy, since its prompt identification enables introducing specific treatment.

Introducción: la tuberculosis es un problema de salud pública mundial, sobre todo en países emergentes. El Mycobacterium tuberculosis es el principal causante de las adenopatías cervicales; las micobacterias no tuberculosas son relativamente frecuentes en el niño y raras en adultos. Objetivo: identificar y establecer la frecuencia de la etiología infecciosa por micobacterias no tuberculosas (MNT) en pacientes adultos mexicanos con linfadenopatias cervicales. Métodos: se estudiaron 85 pacientes mayores de 18 años, con linfadenopatía cervical, 45 con positividad al virus de la inmunodeficiencia humana (VIH) y 40 VIH negativos, sin antecedentes de tratamiento antituberculoso, seleccionados en un hospital de concentración de especialidad de tercer nivel. Se realizó biopsia de nodo linfático para su estudio histopatológico, búsqueda de bacilos ácido-alcohol resistentes, cultivo en el tubo indicador del crecimiento de Mycobacterium BACTEC (MGIT-960) y la identificación de cepa micobacteriana por PCR-RFLP (restriction fragment lenght polymorfism) de hsp65. Resultados: las cepas correspondieron al complejo Mycobacterium tuberculosis en 42 pacientes VIH positivos (93%), dos (4.4%) a M. intracellulare y una (2.2%) a M. gordonae. Las cepas correspondieron al complejo M. tuberculosis en 39 pacientes VIH negativos (97.5%) y una a M. fortuitum (2.5%). Conclusión: la presencia de MNT se encontró en 4.7% de todos los casos. A pesar de su baja frecuencia, deben ser tomadas en cuenta como posible causa de linfadenopatías, porque su identificación oportuna permite instaurar un tratamiento específico.