RESUMEN
The relative fitness of drug-resistant versus susceptible bacteria in an environment dictates resistance prevalence. Estimates for the relative fitness of resistant Mycobacterium tuberculosis (Mtb) strains are highly heterogeneous and mostly derived from in vitro experiments. Measuring fitness in the field allows us to determine how the environment influences the spread of resistance. We designed a household structured, stochastic mathematical model to estimate the fitness costs associated with multidrug resistance (MDR) carriage in Mtb in Lima, Peru during 2010-2013. By fitting the model to data from a large prospective cohort study of TB disease in household contacts, we estimated the fitness, relative to susceptible strains with a fitness of 1, of MDR-Mtb to be 0.32 (95% credible interval: 0.15-0.62) or 0.38 (0.24-0.61), if only transmission or progression to disease, respectively, was affected. The relative fitness of MDR-Mtb increased to 0.56 (0.42-0.72) when the fitness cost influenced both transmission and progression to disease equally. We found the average relative fitness of MDR-Mtb circulating within households in Lima, Peru during 2010-2013 to be significantly lower than concurrent susceptible Mtb If these fitness levels do not change, then existing TB control programmes are likely to keep MDR-TB prevalence at current levels in Lima, Peru.
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Modelos Biológicos , Mycobacterium tuberculosis , Tuberculosis Resistente a Múltiples Medicamentos , Femenino , Humanos , Masculino , Modelos Teóricos , Perú/epidemiología , Prevalencia , Estudios Prospectivos , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/transmisiónRESUMEN
To reduce transmission of tuberculosis (TB) in resource-limited countries where TB remains a major cause of mortality, novel diagnostic tools are urgently needed. We evaluated the fractional concentration of exhaled nitric oxide (FeNO) as an easily measured, noninvasive potential biomarker for diagnosis and monitoring of treatment response in participants with pulmonary TB including multidrug resistant-TB in Lima, Peru. In a longitudinal study however, we found no differences in baseline median FeNO levels between 38 TB participants and 93 age-matched controls (13 parts per billion [ppb] [interquartile range (IQR) = 8-26] versus 15 ppb [IQR = 12-24]), and there was no change over 60 days of treatment (15 ppb [IQR = 10-19] at day 60). Taking this and previous evidence together, we conclude FeNO is not of value in either the diagnosis of pulmonary TB or as a marker of treatment response.
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Óxido Nítrico/análisis , Tuberculosis Pulmonar/diagnóstico , Adulto , Biomarcadores/análisis , Biomarcadores/metabolismo , Estudios de Casos y Controles , Femenino , Humanos , Estudios Longitudinales , Masculino , Óxido Nítrico/metabolismo , Perú , Encuestas y Cuestionarios , Resultado del Tratamiento , Prueba de TuberculinaRESUMEN
BACKGROUND: Cough frequency, and its duration, is a biomarker that can be used in low-resource settings without the need of laboratory culture and has been associated with transmission and treatment response. Radiologic characteristics associated with increased cough frequency may be important in understanding transmission. The relationship between cough frequency and cavitary lung disease has not been studied. METHODS: We analyzed data in 41 adults who were HIV negative and had culture-confirmed, drug-susceptible pulmonary TB throughout treatment. Cough recordings were based on the Cayetano Cough Monitor, and sputum samples were evaluated using microscopic observation drug susceptibility broth culture; among culture-positive samples, bacillary burden was assessed by means of time to positivity. CT scans were analyzed by a US-board-certified radiologist and a computer-automated algorithm. The algorithm evaluated cavity volume and cavitary proximity to the airway. CT scans were obtained within 1 month of treatment initiation. We compared small cavities (≤ 7 mL) and large cavities (> 7 mL) and cavities located closer to (≤ 10 mm) and farther from (> 10 mm) the airway to cough frequency and cough cessation until treatment day 60. RESULTS: Cough frequency during treatment was twofold higher in participants with large cavity volumes (rate ratio [RR], 1.98; P = .01) and cavities located closer to the airway (RR, 2.44; P = .001). Comparably, cough ceased three times faster in participants with smaller cavities (adjusted hazard ratio [HR], 2.89; P = .06) and those farther from the airway (adjusted HR, 3.61;, P = .02). Similar results were found for bacillary burden and culture conversion during treatment. CONCLUSIONS: Cough frequency during treatment is greater and lasts longer in patients with larger cavities, especially those closer to the airway.
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Antituberculosos/uso terapéutico , Tos/epidemiología , Tuberculosis Pulmonar/complicaciones , Adulto , Tos/etiología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Perú/epidemiología , Estudios Prospectivos , Tomografía Computarizada por Rayos X , Tuberculosis Pulmonar/diagnóstico , Tuberculosis Pulmonar/tratamiento farmacológico , Adulto JovenRESUMEN
The differential diagnosis for lymphadenopathy is wide and clinical presentations overlap, making obtaining an accurate diagnosis challenging. We sought to characterize the clinical and radiological characteristics, histological findings, and diagnoses for a cohort of patients with lymphadenopathy of unknown etiology. 121 Peruvian adults with lymphadenopathy underwent lymph node biopsy for microbiological and histopathological evaluation. Mean patient age was 41 years (Interquartile Range 26-52), 56% were males, and 39% were HIV positive. Patients reported fever (31%), weight loss (23%), and headache (22%); HIV infection was associated with fever (P < 0.05) and gastrointestinal symptoms (P < 0.05). Abnormalities were reported in 40% of chest X-rays (N = 101). Physicians suspected TB in 92 patients (76%), lymphoma in 19 patients (16%), and other malignancy in seven patients (5.8%). Histological diagnoses (N = 117) included tuberculosis (34%), hyperplasia (27%), lymphoma (13%), and nonlymphoma malignancy (14%). Hyperplasia was more common (P < 0.001) and lymphoma less common (P = 0.005) among HIV-positive than HIV-negative patients. There was a trend toward reduced frequency of caseous necrosis in samples from HIV-positive than HIV-negative TB patients (67 versus 93%, P = 0.055). The spectrum of diagnoses was broad, and clinical and radiological features correlated poorly with diagnosis. On the basis of clinical features, physicians over-diagnosed TB, and under-diagnosed malignancy. Although this may not be inappropriate in resource-limited settings where TB is the most frequent easily treatable cause of lymphadenopathy, diagnostic delays can be detrimental to patients with malignancy. It is important that patients with lymphadenopathy undergo a full diagnostic work-up including sampling for histological evaluation to obtain an accurate diagnosis.
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Linfadenopatía/diagnóstico , Linfadenopatía/patología , Adulto , Biopsia , Femenino , Humanos , Masculino , Persona de Mediana Edad , PerúRESUMEN
BACKGROUND: Contacts of tuberculosis index cases are at increased risk of developing tuberculosis. Screening, preventive therapy, and surveillance for tuberculosis are underused interventions in contacts, particularly adults. We developed a score to predict risk of tuberculosis in adult contacts of tuberculosis index cases. METHODS: In 2002-06, we recruited contacts aged 15 years or older of index cases with pulmonary tuberculosis who lived in desert shanty towns in Ventanilla, Peru. We followed up contacts for tuberculosis until February, 2016. We used a Cox proportional hazards model to identify index case, contact, and household risk factors for tuberculosis from which to derive a score and classify contacts as low, medium, or high risk. We validated the score in an urban community recruited in Callao, Peru, in 2014-15. FINDINGS: In the derivation cohort, we identified 2017 contacts of 715 index cases, and median follow-up was 10·7 years (IQR 9·5-11·8). 178 (9%) of 2017 contacts developed tuberculosis during 19â147 person-years of follow-up (incidence 0·93 per 100 person-years, 95% CI 0·80-1·08). Risk factors for tuberculosis were body-mass index, previous tuberculosis, age, sustained exposure to the index case, the index case being in a male patient, lower community household socioeconomic position, indoor air pollution, previous tuberculosis among household members, and living in a household with a low number of windows per room. The 10-year risks of tuberculosis in the low-risk, medium-risk, and high-risk groups were, respectively, 2·8% (95% CI 1·7-4·4), 6·2% (4·8-8·1), and 20·6% (17·3-24·4). The 535 (27%) contacts classified as high risk accounted for 60% of the tuberculosis identified during follow-up. The score predicted tuberculosis independently of tuberculin skin test and index-case drug sensitivity results. In the external validation cohort, 65 (3%) of 1910 contacts developed tuberculosis during 3771 person-years of follow-up (incidence 1·7 per 100 person-years, 95% CI 1·4-2·2). The 2·5-year risks of tuberculosis in the low-risk, medium-risk, and high-risk groups were, respectively, 1·4% (95% CI 0·7-2·8), 3·9% (2·5-5·9), and 8·6%· (5·9-12·6). INTERPRETATION: Our externally validated risk score could predict and stratify 10-year risk of developing tuberculosis in adult contacts, and could be used to prioritise tuberculosis control interventions for people most likely to benefit. FUNDING: Wellcome Trust, Department for International Development Civil Society Challenge Fund, Joint Global Health Trials consortium, Bill & Melinda Gates Foundation, Imperial College National Institutes of Health Research Biomedical Research Centre, Foundation for Innovative New Diagnostics, Sir Halley Stewart Trust, WHO, TB REACH, and Innovation for Health and Development.
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Transmisión de Enfermedad Infecciosa , Métodos Epidemiológicos , Tuberculosis/epidemiología , Tuberculosis/transmisión , Adulto , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Perú , Estudios Prospectivos , Medición de Riesgo , Población Rural , Población Urbana , Adulto JovenRESUMEN
INTRODUCTION: Cough is a key symptom of tuberculosis (TB) as well as the main cause of transmission. However, a recent literature review found that cough frequency (number of coughs per hour) in patients with TB has only been studied once, in 1969. The main aim of this study is to describe cough frequency patterns before and after the start of TB treatment and to determine baseline factors that affect cough frequency in these patients. Secondarily, we will evaluate the correlation between cough frequency and TB microbiological resolution. METHODS: This study will select participants with culture confirmed TB from 2 tertiary hospitals in Lima, Peru. We estimated that a sample size of 107 patients was sufficient to detect clinically significant changes in cough frequency. Participants will initially be evaluated through questionnaires, radiology, microscopic observation drug susceptibility broth TB-culture, auramine smear microscopy and cough recordings. This cohort will be followed for the initial 60â days of anti-TB treatment, and throughout the study several microbiological samples as well as 24â h recordings will be collected. We will describe the variability of cough episodes and determine its association with baseline laboratory parameters of pulmonary TB. In addition, we will analyse the reduction of cough frequency in predicting TB cure, adjusted for potential confounders. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the ethics committees at each participating hospital in Lima, Peru, Asociación Benéfica PRISMA in Lima, Peru, the Universidad Peruana Cayetano Heredia in Lima, Peru and Johns Hopkins University in Baltimore, USA. We aim to publish and disseminate our findings in peer-reviewed journals. We also expect to create and maintain an online repository for TB cough sounds as well as the statistical analysis employed.
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Tos/fisiopatología , Tuberculosis Pulmonar/fisiopatología , Adulto , Antituberculosos/uso terapéutico , Protocolos Clínicos , Tos/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis , Perú , Valor Predictivo de las Pruebas , Estudios Prospectivos , Tuberculosis Pulmonar/complicaciones , Tuberculosis Pulmonar/tratamiento farmacológicoRESUMEN
BACKGROUND: Early identification of patients with drug-resistant tuberculosis (DR-TB) increases the likelihood of treatment success and interrupts transmission. Resource-constrained settings use risk profiling to ration the use of drug susceptibility testing (DST). Nevertheless, no studies have yet quantified how many patients with DR-TB this strategy will miss. METHODS: A total of 1,545 subjects, who presented to Lima health centres with possible TB symptoms, completed a clinic-epidemiological questionnaire and provided sputum samples for TB culture and DST. The proportion of drug resistance in this population was calculated and the data was analysed to demonstrate the effect of rationing tests to patients with multidrug-resistant TB (MDR-TB) risk factors on the number of tests needed and corresponding proportion of missed patients with DR-TB. RESULTS: Overall, 147/1,545 (9.5%) subjects had culture-positive TB, of which 32 (21.8%) had DR-TB (MDR, 13.6%; isoniazid mono-resistant, 7.5%; rifampicin mono-resistant, 0.7%). A total of 553 subjects (35.8%) reported one or more MDR-TB risk factors; of these, 506 (91.5%; 95% CI, 88.9-93.7%) did not have TB, 32/553 (5.8%; 95% CI, 3.4-8.1%) had drug-susceptible TB, and only 15/553 (2.7%; 95% CI, 1.5-4.4%) had DR-TB. Rationing DST to those with an MDR-TB risk factor would have missed more than half of the DR-TB population (17/32, 53.2%; 95% CI, 34.7-70.9). CONCLUSIONS: Rationing DST based on known MDR-TB risk factors misses an unacceptable proportion of patients with drug-resistance in settings with ongoing DR-TB transmission. Investment in diagnostic services to allow universal DST for people with presumptive TB should be a high priority.
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Asignación de Recursos para la Atención de Salud , Disparidades en el Estado de Salud , Tamizaje Masivo/normas , Tuberculosis Resistente a Múltiples Medicamentos/diagnóstico , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Adulto , Pruebas Diagnósticas de Rutina/estadística & datos numéricos , Femenino , Asignación de Recursos para la Atención de Salud/normas , Recursos en Salud , Accesibilidad a los Servicios de Salud/normas , Humanos , Masculino , Tamizaje Masivo/métodos , Pruebas de Sensibilidad Microbiana/estadística & datos numéricos , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Factores de Riesgo , Esputo/microbiología , Resultado del TratamientoRESUMEN
Improved tuberculosis (TB) diagnostics are required. Induced sputum sampling is superior to spontaneous sputum analysis for diagnosis of pulmonary TB. Therefore, we examined the applicability of induced sputum in primary health centers of the Peruvian TB program and studied the safety and tolerability of this procedure. We show that induced sputum is safe, inexpensive, and well-tolerated in a resource-limited environment. Widespread use of induced sputum at primary health centers can be implemented and may improve TB diagnosis.
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Atención Primaria de Salud/métodos , Solución Salina Hipertónica/administración & dosificación , Solución Salina Hipertónica/efectos adversos , Esputo/microbiología , Tuberculosis/diagnóstico , Adulto , Femenino , Humanos , Masculino , Perú/epidemiología , Tuberculosis/epidemiologíaRESUMEN
BACKGROUND: Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research. MATERIALS AND METHODS: We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (Nâ=â2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA. RESULTS: Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CIâ=â1.6-2.8%) with prevalence up to 4.3% (42/977) (95% CIâ=â3.1-5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CIâ=â1.0-2.0%). Prevalence up to 2.9% (28/977) (95% CIâ=â1.9-4.1%) by community was observed. CONCLUSION/SIGNIFICANCE: This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.
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Anticestodos/administración & dosificación , Neurocisticercosis/tratamiento farmacológico , Neurocisticercosis/epidemiología , Niclosamida/administración & dosificación , Taenia solium/aislamiento & purificación , Adolescente , Adulto , Animales , Niño , Conducta Cooperativa , Estudios Transversales , Heces/parasitología , Femenino , Humanos , Masculino , Neurocisticercosis/parasitología , Peace Corps , Perú/epidemiología , Prevalencia , Prohibitinas , Investigadores , Población Rural , Taenia solium/efectos de los fármacos , Estados Unidos , Voluntarios , Adulto JovenRESUMEN
BACKGROUND: Even though the WHO-endorsed, non-commercial MODS assay offers rapid, reliable TB liquid culture and phenotypic drug susceptibility testing (DST) at lower cost than any other diagnostic, uptake has been patchy. In part this reflects misperceptions about in-house assay quality assurance, but user convenience of one-stop procurement is also important. A commercial MODS kit was developed by Hardy Diagnostics (Santa Maria, CA, USA) with PATH (Seattle, WA, USA) to facilitate procurement, simplify procedures through readymade media, and enhance safety with a sealing silicone plate lid. Here we report the results from a large-scale field evaluation of the MODS kit in a government service laboratory. METHODS & FINDINGS: 2446 sputum samples were cultured in parallel in Lowenstein-Jensen (LJ), conventional MODS and in the MODS kit. MODS kit DST was compared with conventional MODS (direct) DST and proportion method (indirect) DST. 778 samples (31.8%) were Mycobacterium tuberculosis culture-positive. Compared to conventional MODS the sensitivity, specificity, positive, and negative predictive values (95% confidence intervals) of the MODS Kit were 99.3% (98.3-99.8%), 98.3% (97.5-98.8%), 95.8% (94.0-97.1%), and 99.7% (99.3-99.9%). Median (interquartile ranges) time to culture-positivity (and rifampicin and isoniazid DST) was 10 (9-13) days for conventional MODS and 8.5 (7-11) for MODS Kit (p<0.01). Direct rifampicin and isoniazid DST in MODS kit was almost universally concordant with conventional MODS (97.9% agreement, 665/679 evaluable samples) and reference indirect DST (97.9% agreement, 687/702 evaluable samples). CONCLUSIONS: MODS kit delivers performance indistinguishable from conventional MODS and offers a convenient, affordable alternative with enhanced safety from the sealing silicone lid. The availability in the marketplace of this platform, which conforms to European standards (CE-marked), readily repurposed for second-line DST in the near future, provides a fresh opportunity for improving equity of access to TB diagnosis and first and second-line DST in settings where the need is greatest.
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Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis , Juego de Reactivos para Diagnóstico , Tuberculosis Resistente a Múltiples Medicamentos/diagnóstico , Tuberculosis/diagnóstico , Antituberculosos/farmacología , Humanos , Isoniazida/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Perú , Reproducibilidad de los Resultados , Rifampin/farmacología , Sensibilidad y Especificidad , Esputo/microbiologíaRESUMEN
BACKGROUND: Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years. METHODS: Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosis-exposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained. RESULTS: Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001). CONCLUSIONS: The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis.
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Aglomeración , Composición Familiar , Luz Solar , Tuberculosis/epidemiología , Vitamina D/sangre , Adulto , Estudios de Cohortes , Femenino , Humanos , Incidencia , Ensayos de Liberación de Interferón gamma , Masculino , Perú/epidemiología , Estaciones del Año , Prueba de TuberculinaRESUMEN
Multidrug-resistant tuberculosis (TB) threatens TB control worldwide. The microscopic observation drug susceptibility (MODS) assay is a low-cost, high-performance TB diagnostic tool for rapid liquid culture and direct isoniazid and rifampicin drug susceptibility testing (DST). The objective of this study was to explore the potential for extending the MODS assay to rapid second-line DST and to identify critical concentrations of candidate drugs for prospective testing. Sputum samples from 94 TB culture-positive patients receiving second-line TB agents were cultured following standardised MODS protocols, with a range of titrations of antimicrobial drugs added. Critical concentrations were determined using a modified Kaplan-Meier survival curve analysis. Candidate critical concentrations were determined for capreomycin (10 µg·mL(-1)), ciprofloxacin (1.25 µg·mL(-1)), cycloserine (40 µg·mL(-1)), ethambutol (10 µg·mL(-1)), ethionamide (5 µg·mL(-1)), kanamycin (5 µg·mL(-1)), para-aminosalicylic acid (10 µg·mL(-1)) and streptomycin (10 µg·mL(-1)). No cut-off point was identified for the other second-line drugs or for pyrazinamide. At particular concentrations of some second-line TB drugs this novel Kaplan-Meier analysis clearly differentiated populations that were susceptible or resistant. These candidate critical concentrations should now be tested in a range of epidemiological settings to define the performance of direct, second-line TB DST with MODS, offering potential low-cost second-line TB DST capacity.
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Antituberculosos/uso terapéutico , Pruebas de Sensibilidad Microbiana/métodos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Relación Dosis-Respuesta a Droga , Farmacorresistencia Bacteriana Múltiple , Humanos , Perú , Fenotipo , Curva ROC , Esputo/microbiología , Tuberculosis Resistente a Múltiples Medicamentos/diagnósticoRESUMEN
BACKGROUND: Effective tuberculosis control is compromised by a lack of clarity about the timeframe of viable Mycobacterium tuberculosis shedding after treatment initiation under programmatic conditions. This study quantifies time to conversion from smear and culture positivity to negativity in unselected tuberculosis patients receiving standardized therapy in a directly observed therapy short-course (DOTS) program. METHODS: Longitudinal cohort study following up 93 adults initiating tuberculosis therapy in Lima, Peru. Baseline culture and drug susceptibility tests (DSTs) were performed using the MBBacT, proportion, and microscopic observation drug susceptibility (MODS) methods. Smear microscopy and MODS liquid culture were performed at baseline and weekly for 4 weeks then every other week for 26 weeks. RESULTS: Median conversion time from culture positivity to culture negativity of 38.5 days was unaffected by baseline smear status. Patients with fully susceptible tuberculosis had a median time to culture conversion of 37 days; 10% remained culture positive at day 60. Delayed culture conversion was associated with multidrug resistance, regardless of DST method used; non-multidrug resistance as defined by the proportion method and MODS (but not MBBacT) was also associated with delay. Persistent day 60 smear positivity yielded positive and negative predictive values of 67% and 92%, respectively, for detecting multidrug resistance. CONCLUSIONS: Smear and culture conversion in treated tuberculosis patients takes longer than is conventionally believed, even with fully susceptible disease, and must be accounted for in tuberculosis treatment and prevention programs. Persistent day 60 smear positivity is a poor predictor of multidrug resistance. The industrialized-world convention of universal baseline DST for tuberculosis patients should become the standard of care in multidrug resistance-affected resource-limited settings.
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Antituberculosos/uso terapéutico , Derrame de Bacterias , Terapia por Observación Directa , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis/tratamiento farmacológico , Tuberculosis/microbiología , Adulto , Animales , Técnicas Bacteriológicas , Estudios de Cohortes , Farmacorresistencia Bacteriana Múltiple , Femenino , Humanos , Estudios Longitudinales , Masculino , Pruebas de Sensibilidad Microbiana , Microscopía , Persona de Mediana Edad , Perú , Esputo/microbiología , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND: Active tuberculosis (TB) must be excluded before initiating isoniazid preventive therapy (IPT) in persons infected with human immunodeficiency virus (HIV), but currently used screening strategies have poor sensitivity and specificity and high patient attrition rates. Liquid TB culture is now recommended for the detection of Mycobacterium tuberculosis in individuals suspected of having TB. This study compared the efficacy, effectiveness, and speed of the microscopic observation drug susceptibility (MODS) assay with currently used strategies for TB screening before IPT in HIV-infected persons. METHODS: A total of 471 HIV-infected IPT candidates at 3 hospitals in Lima, Peru, were enrolled in a prospective comparison of TB screening strategies, including laboratory, clinical, and radiographic assessments. RESULTS: Of 435 patients who provided 2 sputum samples, M. tuberculosis was detected in 27 (6.2%) by MODS culture, 22 (5.1%) by Lowenstein-Jensen culture, and 7 (1.6%) by smear. Of patients with any positive microbiological test result, a MODS culture was positive in 96% by 14 days and 100% by 21 days. The MODS culture simultaneously detected multidrug-resistant TB in 2 patients. Screening strategies involving combinations of clinical assessment, chest radiograph, and sputum smear were less effective than 2 liquid TB cultures in accurately diagnosing and excluding TB (P<.01). Screening strategies that included nonculture tests had poor sensitivity and specificity. CONCLUSIONS: MODS culture identified and reliably excluded cases of pulmonary TB more accurately than other screening strategies, while providing results significantly faster than Lowenstein-Jensen culture. Streamlining of the ruling out of TB through the use of liquid culture-based strategies could help facilitate the massive up-scaling of IPT required to reduce HIV and TB morbidity and mortality.
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Antituberculosos/administración & dosificación , Técnicas de Tipificación Bacteriana/métodos , Infecciones por VIH/microbiología , Isoniazida/administración & dosificación , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis/diagnóstico , Adulto , Técnicas de Tipificación Bacteriana/economía , Distribución de Chi-Cuadrado , Farmacorresistencia Bacteriana , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana/economía , Microscopía/métodos , Estudios Prospectivos , Sensibilidad y Especificidad , Manejo de Especímenes , Esputo/microbiología , Factores de Tiempo , Tuberculosis/microbiología , Tuberculosis/prevención & control , Tuberculosis/virologíaRESUMEN
OBJECTIVE: To evaluate the effects of diarrhea on appetite among Peruvian children age 12 to 71 months and to assess whether elevated plasma levels of peptide YY, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta contribute to anorexia in this population. STUDY DESIGN: A total of 46 Peruvian children with diarrhea and 46 healthy controls underwent an observed feeding trial that was repeated when cases were healthy. Blood samples were obtained from 30 cases and 30 controls at the first trial and from 30 cases at the second trial and assayed for peptide YY, TNF-alpha, and IL-1beta. RESULTS: In the cases, mean consumption was less when sick than when healthy. The mean plasma level of peptide YY was higher for cases than controls and higher for cases when sick than when healthy. TNF-alpha levels were higher in cases than controls at visit 1 and also higher in cases when sick than when healthy. There were no differences in IL-1beta levels between cases and controls or between cases when sick and healthy. Peptide YY levels in children with diarrhea correlated with the likelihood of them eating less when sick than when healthy. CONCLUSIONS: Elevated serum peptide YY may be a mechanism for anorexia in children with diarrhea.
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Anorexia/complicaciones , Diarrea/diagnóstico , Hormonas Gastrointestinales/metabolismo , Mucosa Intestinal/metabolismo , Péptido YY/fisiología , Anorexia/metabolismo , Apetito , Estudios de Casos y Controles , Preescolar , Diarrea/microbiología , Diarrea/patología , Femenino , Humanos , Lactante , Interleucina-1beta/metabolismo , Masculino , Péptido YY/metabolismo , Resultado del Tratamiento , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
BACKGROUND: Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. METHODS AND FINDINGS: The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. CONCLUSIONS: Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion.
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Microbiología del Aire , Infección Hospitalaria/prevención & control , Tuberculosis/prevención & control , Ventilación , Infección Hospitalaria/transmisión , Arquitectura y Construcción de Hospitales , Hospitales , Humanos , Perú , Tuberculosis/transmisiónRESUMEN
In 50 healthy Peruvian shantytown residents, zinc cream applied to tuberculosis skin-test sites caused a 32% increase in induration compared with placebo cream. Persons with lower plasma zinc had smaller skin-test reactions and greater augmentation with zinc cream. Zinc deficiency caused false-negative skin-test results, and topical zinc supplementation augmented antimycobacterial immune responses enough to improve diagnosis.
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Piel/efectos de los fármacos , Prueba de Tuberculina/normas , Tuberculosis/diagnóstico , Zinc/deficiencia , Zinc/farmacología , Administración Tópica , Adulto , Diagnóstico Diferencial , Método Doble Ciego , Reacciones Falso Negativas , Femenino , Humanos , Masculino , Estado Nutricional , Perú , Reproducibilidad de los Resultados , Factores de Riesgo , Sensibilidad y Especificidad , Clase Social , Factores Socioeconómicos , Oligoelementos/sangre , Oligoelementos/farmacología , Prueba de Tuberculina/métodos , Zinc/sangreRESUMEN
Decades of social and political unrest have contributed to the urbanization of the population of Peru with large-scale migration from rural Andean and Amazonian communities to overcrowded shantytowns around Lima. We administered a face-to-face survey questionnaire to 116 patients with suspected and proven tuberculosis (TB) in northern Lima to determine the extent to which the use of traditional therapies from indigenous regions persists and the impact of any such use on TB control. Sixty-three percent of participants reported some form of self-treatment prior to presentation to the National Tuberculosis Program; 52% of them used traditional remedies. Symptom duration was longer among self-remedy users than non-users (median = 25 versus 15 days; P = 0.07) and among those exclusively using western remedies rather than traditional remedies (median = 30 versus 15 days; P = 0.01). We thus found no evidence that use of traditional remedies has an appreciable effect on diagnostic delay in Lima.
Asunto(s)
Antituberculosos/administración & dosificación , Medicina Tradicional , Tuberculosis/prevención & control , Adulto , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Perú/epidemiología , Plantas MedicinalesRESUMEN
Taenia solium neurocysticercosis is a common cause of epileptic seizures and other neurological morbidity in most developing countries. It is also an increasingly common diagnosis in industrialized countries because of immigration from areas where it is endemic. Its clinical manifestations are highly variable and depend on the number, stage, and size of the lesions and the host's immune response. In part due to this variability, major discrepancies exist in the treatment of neurocysticercosis. A panel of experts in taeniasis/cysticercosis discussed the evidence on treatment of neurocysticercosis for each clinical presentation, and we present the panel's consensus and areas of disagreement. Overall, four general recommendations were made: (i) individualize therapeutic decisions, including whether to use antiparasitic drugs, based on the number, location, and viability of the parasites within the nervous system; (ii) actively manage growing cysticerci either with antiparasitic drugs or surgical excision; (iii) prioritize the management of intracranial hypertension secondary to neurocysticercosis before considering any other form of therapy; and (iv) manage seizures as done for seizures due to other causes of secondary seizures (remote symptomatic seizures) because they are due to an organic focus that has been present for a long time.