Impact of HIV on mortality among patients treated for tuberculosis in Lima, Peru: a prospective cohort study.

BACKGROUND: Human immunodeficiency virus (HIV)-associated tuberculosis deaths have decreased worldwide over the past decade. We sought to evaluate the effect of HIV status on tuberculosis mortality among patients undergoing treatment for tuberculosis in Lima, Peru, a low HIV prevalence setting. METHODS: We conducted a prospective cohort study of patients treated for tuberculosis between 2005 and 2008 in two adjacent health regions in Lima, Peru (Lima Ciudad and Lima Este). We constructed a multivariate Cox proportional hazards model to evaluate the effect of HIV status on mortality during tuberculosis treatment. RESULTS: Of 1701 participants treated for tuberculosis, 136 (8.0%) died during tuberculosis treatment. HIV-positive patients constituted 11.0% of the cohort and contributed to 34.6% of all deaths. HIV-positive patients were significantly more likely to die (25.1 vs. 5.9%, P < 0.001) and less likely to be cured (28.3 vs. 39.4%, P = 0.003). On multivariate analysis, positive HIV status (hazard ratio [HR] = 6.06; 95% confidence interval [CI], 3.96-9.27), unemployment (HR = 2.24; 95% CI, 1.55-3.25), and sputum acid-fast bacilli smear positivity (HR = 1.91; 95% CI, 1.10-3.31) were significantly associated with a higher hazard of death. CONCLUSIONS: We demonstrate that positive HIV status was a strong predictor of mortality among patients treated for tuberculosis in the early years after Peru started providing free antiretroviral therapy. As HIV diagnosis and antiretroviral therapy provision are more widely implemented for tuberculosis patients in Peru, future operational research should document the changing profile of HIV-associated tuberculosis mortality.

Transmission of Multidrug-Resistant and Drug-Susceptible Tuberculosis within Households: A Prospective Cohort Study.

BACKGROUND: The "fitness" of an infectious pathogen is defined as the ability of the pathogen to survive, reproduce, be transmitted, and cause disease. The fitness of multidrug-resistant tuberculosis (MDRTB) relative to drug-susceptible tuberculosis is cited as one of the most important determinants of MDRTB spread and epidemic size. To estimate the relative fitness of drug-resistant tuberculosis cases, we compared the incidence of tuberculosis disease among the household contacts of MDRTB index patients to that among the contacts of drug-susceptible index patients. METHODS AND FINDINGS: This 3-y (2010-2013) prospective cohort household follow-up study in South Lima and Callao, Peru, measured the incidence of tuberculosis disease among 1,055 household contacts of 213 MDRTB index cases and 2,362 household contacts of 487 drug-susceptible index cases. A total of 35/1,055 (3.3%) household contacts of 213 MDRTB index cases developed tuberculosis disease, while 114/2,362 (4.8%) household contacts of 487 drug-susceptible index patients developed tuberculosis disease. The total follow-up time for drug-susceptible tuberculosis contacts was 2,620 person-years, while the total follow-up time for MDRTB contacts was 1,425 person-years. Using multivariate Cox regression to adjust for confounding variables including contact HIV status, contact age, socio-economic status, and index case sputum smear grade, the hazard ratio for tuberculosis disease among MDRTB household contacts was found to be half that for drug-susceptible contacts (hazard ratio 0.56, 95% CI 0.34-0.90, p = 0.017). The inference of transmission in this study was limited by the lack of genotyping data for household contacts. Capturing incident disease only among household contacts may also limit the extrapolation of these findings to the community setting. CONCLUSIONS: The low relative fitness of MDRTB estimated by this study improves the chances of controlling drug-resistant tuberculosis. However, fitter multidrug-resistant strains that emerge over time may make this increasingly difficult.

Characterization of the genetic diversity of extensively-drug resistant Mycobacterium tuberculosis clinical isolates from pulmonary tuberculosis patients in Peru.

BACKGROUND: Peru holds the fourth highest burden of tuberculosis in the Americas. Despite an apparently well-functioning DOTS control program, the prevalence of multidrug resistant tuberculosis (MDR-TB) continues to increase. To worsen this situation, cases of extensively drug resistance tuberculosis (XDR-TB) have been detected. Little information exists about the genetic diversity of drug-susceptible vs. MDR-TB and XDR-TB. METHODS: Cryopreserved samples of XDR strains from 2007 to 2009 (second semester), were identified and collected. Starting from 227 frozen samples, a total of 142 XDR-TB strains of Mycobacterium tuberculosis complex (MTBC; 1 isolate per patient) were retained for this study. Each strain DNA was analyzed by spoligotyping and the 15-loci Mycobacterial Interspersed Repetitive Unit (MIRU-15). RESULTS: Among the 142 isolates analyzed, only 2 samples (1.41%) could not be matched to any lineage. The most prevalent sublineage was Haarlem (43.66%), followed by T (27.46%), LAM (16.2%), Beijing (9.15%), and X clade (1.41%). Spoligotype analysis identified clustering for 128/142 (90.1%) isolates vs. 49/142 (34.5%) with MIRUs. Of the samples, 90.85% belonged to retreated patients. The drug resistant profile demonstrated that 62.67% showed resistance to injectable drugs capreomycin (CAP) and kanamycin (KAN) vs. 15.5% to CAP alone and 21.8% to KAN alone. The SIT219/T1 and SIT50/H3 were the most prevalent patterns in our study. The spoligoforest analysis showed that SIT53/T1 was at the origin of many of the T lineage strains as well as a big proportion of Haarlem lineage strains (SIT50/H3, followed by SIT47/H1, SIT49/H3, and SIT2375/H1), as opposed to the SIT1/Beijing strains that did not appear to evolve into minor Beijing sublineages among the XDR-TB strains. CONCLUSION: In contrast with other Latin-American countries where LAM sublineage is the most predominant, we found the Haarlem to be the most common followed by T sublineage among the XDR-TB strains.

Reducing communication delays and improving quality of care with a tuberculosis laboratory information system in resource poor environments: a cluster randomized controlled trial.

BACKGROUND: Lost, delayed or incorrect laboratory results are associated with delays in initiating treatment. Delays in treatment for Multi-Drug Resistant Tuberculosis (MDR-TB) can worsen patient outcomes and increase transmission. The objective of this study was to evaluate the impact of a laboratory information system in reducing delays and the time for MDR-TB patients to culture convert (stop transmitting). SETTING: 78 primary Health Centers (HCs) in Lima, Peru. Participants lived within the catchment area of participating HCs and had at least one MDR-TB risk factor. The study design was a cluster randomized controlled trial with baseline data. The intervention was the e-Chasqui web-based laboratory information system. Main outcome measures were: times to communicate a result; to start or change a patient's treatment; and for that patient to culture convert. RESULTS: 1671 patients were enrolled. Intervention HCs took significantly less time to receive drug susceptibility test (DST) (median 11 vs. 17 days, Hazard Ratio 0.67 [0.62-0.72]) and culture (5 vs. 8 days, 0.68 [0.65-0.72]) results. The time to treatment was not significantly different, but patients in intervention HCs took 16 days (20%) less time to culture convert (p = 0.047). CONCLUSIONS: The eChasqui system reduced the time to communicate results between laboratories and HCs and time to culture conversion. It is now used in over 259 HCs covering 4.1 million people. This is the first randomized controlled trial of a laboratory information system in a developing country for any disease and the only study worldwide to show clinical impact of such a system. TRIAL REGISTRATION: ClinicalTrials.gov NCT01201941.

[Mycobacterium avium lung infection in HIV/AIDS patient: first report in Peru]. / Infección pulmonar por Mycobacterium avium en paciente VIH/SIDA: primer reporte en Perú

The Mycobacterium avium complex (MAC) is a pathogen found in the environment which causes infections in immunocompetent and immunocompromised patients. One case is presented: an HIV positive, 38 year old male patient, infected with P. jirovecii and apparently infected with Mycobacterium tuberculosis since 2009. He was treated with antibiotic therapy for pneumocystosis and antituberculosis (TB) therapy, which achieved a partial improvement. In 2012, the patient underwent a culture test and new anti TB treatment. Upon suspicion of a drug resistant TB strain, it was recommended to perform the mycobacterial identification. The culture test was positive and the genotypic result was positive for MAC. The first case of an HIV/AIDS patient with MAC lung infection in Peru is reported, as well as a brief review of the epidemiological, clinical and treatment aspects to the case.

Infección pulmonar por Mycobacterium avium en paciente VIH/SIDA: Primer reporte en Perú / Mycobacterium avium lung infection in HIV/AIDS patient: First report in Peru

El complejo Mycobacterium avium (MAC) es un patógeno que se encuentra en el medioambiente y causa infecciones tanto en pacientes inmunocompetentes como inmunocomprometidos. Se presenta el caso de un paciente VIH positivo varón de 38 años infectado por P. jirovecii y aparentemente infectado por Mycobacterium tuberculosis desde el año 2009, el cual fue tratado con antibioticoterapia para pneumocistosis y terapia antituberculosis (TB) logrando mejoría parcial. En el año 2012 se le realizó nuevamente examen de cultivo y un nuevo tratamiento anti TB, frente a la sospecha de estar en presencia de una cepa de TB multidrogorresistente se recomienda realizar la identificación micobacteriana. El examen de cultivo fue positivo y el resultado genotípico resultó positivo para MAC. Se reporta el primer caso de un paciente VIH/SIDA con infección pulmonar por MAC en el Perú, así como una breve revisión de los aspectos epidemiológicos, clínicos y de tratamiento.

The Mycobacterium avium complex (MAC) is a pathogen found in the environment which causes infections in immunocompetent and immunocompromised patients. One case is presented: an HIV positive, 38 year old male patient, infected with P. jirovecii and apparently infected with Mycobacterium tuberculosis since 2009. He was treated with antibiotic therapy for pneumocystosis and antituberculosis (TB) therapy, which achieved a partial improvement. In 2012, the patient underwent a culture test and new anti TB treatment. Upon suspicion of a drug resistant TB strain, it was recommended to perform the mycobacterial identification. The culture test was positive and the genotypic result was positive for MAC. The first case of an HIV/AIDS patient with MAC lung infection in Peru is reported, as well as a brief review of the epidemiological, clinical and treatment aspects to the case.

Use of spatial information to predict multidrug resistance in tuberculosis patients, Peru.

To determine whether spatiotemporal information could help predict multidrug resistance at the time of tuberculosis diagnosis, we investigated tuberculosis patients who underwent drug susceptibility testing in Lima, Peru, during 2005-2007. We found that crude representation of spatial location at the level of the health center improved prediction of multidrug resistance.

[Molecular test Genotype® MTBDRplus, an alternative to rapid detection of multidrug resistance tuberculosis]. / Prueba molecular Genotype® MTBDRplus, una alternativa para la detección rápida de tuberculosis multidrogorresistente.

The Genotype®MTBDRplus molecular test is a method that allows identification of the most frequent mutations associated with resistance to major first-line antituberculosis drugs, Isoniazid (INH) and Rifampicin (RFP). The aim of this study was to evaluate the performance of the molecular test with culture and smear- positive sputum samples. We evaluated 95 cultures and 100 sputum samples with resistance profiles previously determined by the reference method "Agar Plate Proportions" (APP). The molecular test from cultures showed a sensitivity of 100 %, 97,5 % and 96,97 % for RIF, INH and MDR respectively while from sputums the sensitivity was 95,65 %, 96,77 % and 95,24 % for RIF, INH and MDR respectively. We conclude that the molecular test Genotype®MTBDRplus is a very useful tool to detect resistance to isoniazid and rifampicin simultaneously (MDR-TB) in up to 72 hours from sputum samples or cultures.

Identifying multidrug resistant tuberculosis transmission hotspots using routinely collected data.

In most countries with large drug resistant tuberculosis epidemics, only those cases that are at highest risk of having MDRTB receive a drug sensitivity test (DST) at the time of diagnosis. Because of this prioritized testing, identification of MDRTB transmission hotspots in communities where TB cases do not receive DST is challenging, as any observed aggregation of MDRTB may reflect systematic differences in how testing is distributed in communities. We introduce a new disease mapping method, which estimates this missing information through probability-weighted locations, to identify geographic areas of increased risk of MDRTB transmission. We apply this method to routinely collected data from two districts in Lima, Peru over three consecutive years. This method identifies an area in the eastern part of Lima where previously untreated cases have increased risk of MDRTB. This may indicate an area of increased transmission of drug resistant disease, a finding that may otherwise have been missed by routine analysis of programmatic data. The risk of MDR among retreatment cases is also highest in these probable transmission hotspots, though a high level of MDR among retreatment cases is present throughout the study area. Identifying potential multidrug resistant tuberculosis (MDRTB) transmission hotspots may allow for targeted investigation and deployment of resources.

Targeted drug-resistance testing strategy for multidrug-resistant tuberculosis detection, Lima, Peru, 2005-2008.

The Peruvian National Tuberculosis Control Program issued guidelines in 2006 specifying criteria for culture and drug-susceptibility testing (DST), including district-level rapid DST. All patients referred for culture and DST in 2 districts of Lima, Peru, during January 2005-November 2008 were monitored prospectively. Of 1,846 patients, 1,241 (67.2%) had complete DST results for isoniazid and rifampin; 419 (33.8%) patients had multidrug-resistant (MDR) TB at the time of referral. Among patients with new smear-positive TB, household contact and suspected category I failure were associated with MDR TB, compared with concurrent regional surveillance data. Among previously treated patients with smear-positive TB, adult household contact, suspected category II failure, early relapse after category I, and multiple previous TB treatments were associated with MDR TB, compared with concurrent regional surveillance data. The proportion of MDR TB detected by using guidelines was higher than that detected by a concurrent national drug-resistance survey, indicating that the strategy effectively identified patients for DST.

Full impact of laboratory information system requires direct use by clinical staff: cluster randomized controlled trial.

OBJECTIVE: To evaluate the time to communicate laboratory results to health centers (HCs) between the e-Chasqui web-based information system and the pre-existing paper-based system. METHODS: Cluster randomized controlled trial in 78 HCs in Peru. In the intervention group, 12 HCs had web access to results via e-Chasqui (point-of-care HCs) and forwarded results to 17 peripheral HCs. In the control group, 22 point-of-care HCs received paper results directly and forwarded them to 27 peripheral HCs. Baseline data were collected for 15 months. Post-randomization data were collected for at least 2 years. Comparisons were made between intervention and control groups, stratified by point-of-care versus peripheral HCs. RESULTS: For point-of-care HCs, the intervention group took less time to receive drug susceptibility tests (DSTs) (median 9 vs 16 days, p<0.001) and culture results (4 vs 8 days, p<0.001) and had a lower proportion of 'late' DSTs taking >60 days to arrive (p<0.001) than the control. For peripheral HCs, the intervention group had similar communication times for DST (median 22 vs 19 days, p=0.30) and culture (10 vs 9 days, p=0.10) results, as well as proportion of 'late' DSTs (p=0.57) compared with the control. CONCLUSIONS: Only point-of-care HCs with direct access to the e-Chasqui information system had reduced communication times and fewer results with delays of >2 months. Peripheral HCs had no benefits from the system. This suggests that health establishments should have point-of-care access to reap the benefits of electronic laboratory reporting.

Vigilancia nacional de la resistencia a medicamentos antituberculosos, Perú 2005-2006 / National surveillance of anti-tuberculosis drug resistance, Peru 2005-2006

Objetivo. Determinar la prevalencia de resistencia a medicamentos antituberculosos en el Perú. Materiales ymétodos. Se realizó un muestreo por conglomerados en las 33 regiones de salud de Perú. Se utilizó el método de lasproporciones de Canetti en medio sólido Lowenstein Jensen para la susceptibilidad de Mycobacterium tuberculosis a medicamentos antituberculosos con isoniacida (INH) rifampicina (RMP), estreptomicina (SM) y etambutol (EMB). Las cepas con resultado de TB MDR se sometieron a susceptibilidad a medicamentos de segunda línea por el método delas proporciones en agar 7H10, en placas. Resultados. Se analizaron 1809 cultivos de pacientes nuevos y 360 de antes tratados. El 51,6 por ciento residía en Lima y el 59,3 por ciento fueron varones. La prevalencia nacional de la resistencia primaria fue de 23,2 por ciento (IC95 por ciento: 21,3 - 25,1) y la resistencia adquirida fue de 41,7 por ciento (IC95 por ciento: 36,5 - 46,8). Se detectó 180 casos de TB MDR de los cuales la prevalencia de TB MDR primaria fue 5,3 por ciento (IC95 por ciento: 4,2 - 6,3) y la adquirida fue de 23,6 por ciento (IC95 por ciento:19,2 û 28,0). El 20 por ciento de aislamientos de pacientes nunca tratados en Lima fueron resistentes a INH o RIF. La resistencia global y la TB MDR primarias fueron más prevalentes en Lima que en el resto del país. La TB XDR estuvo presente en el 5,9 por ciento de pacientes con TB MDR y el 36 por ciento de las cepas de TB MDR fueron resistentes a por lo menos una droga de segunda línea. Conclusiones. Comparado con los estudios previos, la resistencia a drogas antituberculosas primaria y adquirida se ha incrementado significativamente en los últimos 10 años en Perú.

Objective. To determine the anti-tuberculosis drug resistance prevalence in Peru. Material and methods. We performed a conglomerated sampling in 33 health regions from Peru. We used a Canneti proportions method in solid medium L-J for testing Mycobacterium tuberculosis susceptibility with isoniazid (INH) rifampicin (RMP), streptomycin (SM) and ethambutol (EMB). Strains with TB MDR was evaluated to second line drug susceptibility by proportion methods in 7H10 agar in plates. Results. We analyzed 1809 cultures from new patients and 360 pre treated. 51.6 coming from Lima and 59.3 per cent were males. The national prevalence of primary resistance was 23.2 per cent (CI95 per cent: 21.3 - 25.1) and acquired resistance was 41.7 per cent (95 per cent CI: 36.5 - 46.8). We detected 180 TB MDR cases, the prevalence of primary TB MDR was5.3 per cent (95 per cent CI: 4.2 - 6.3) and acquired was 23.6 per cent (95 per cent CI: 19.2 - 28.0). 20% of never treated patients isolated wereresistant to INH or RIF. Global resistance and primary TB MDR were more prevalent in Lima than rest of the country. TB XDR was present in 5.9 per cent of patients with TB MDR and 36 per cent of TB MDR strains were resistant at least one secondline drug. Conclusions. Compared with previous studies, primary and acquired anti-tuberculosis drug resistant have significantly increased in the last 10 years in Peru.

Management of extensively drug-resistant tuberculosis in Peru: cure is possible.

AIM: To describe the incidence of extensive drug-resistant tuberculosis (XDR-TB) reported in the Peruvian National multidrug-resistant tuberculosis (MDR-TB) registry over a period of more than ten years and present the treatment outcomes for a cohort of these patients. METHODS: From the Peruvian MDR-TB registry we extracted all entries that were approved for second-line anti-TB treatment between January 1997 and June of 2007 and that had Drug Susceptibility Test (DST) results indicating resistance to both rifampicin and isoniazid (i.e. MDR-TB) in addition to results for at least one fluoroquinolone and one second-line injectable (amikacin, capreomycin and kanamycin). RESULTS: Of 1,989 confirmed MDR-TB cases with second-line DSTs, 119(6.0%) XDR-TB cases were detected between January 1997 and June of 2007. Lima and its metropolitan area account for 91% of cases, a distribution statistically similar to that of MDR-TB. A total of 43 XDR-TB cases were included in the cohort analysis, 37 of them received ITR. Of these, 17(46%) were cured, 8(22%) died and 11(30%) either failed or defaulted treatment. Of the 14 XDR-TB patients diagnosed as such before ITR treatment initiation, 10 (71%) were cured and the median conversion time was 2 months. CONCLUSION: In the Peruvian context, with long experience in treating MDR-TB and low HIV burden, although the overall cure rate was poor, a large proportion of XDR-TB patients can be cured if DST to second-line drugs is performed early and treatment is delivered according to the WHO Guidelines.

Human Mycobacterium bovis infection in ten Latin American countries.

The aim of this work was to obtain the best possible estimate of the relevance of bovine tuberculosis (BTB) in humans in Argentina, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, Peru, Uruguay and Venezuela. Sources of information were a questionnaire filled by the participant laboratories, and a search of published literature (1970-2007). Only four of these countries reported bacteriologically confirmed cases of BTB in humans. Most of these were diagnosed in Argentina, where the mean percentage of Mycobacterium bovis cases in relation to those due to Mycobacterium tuberculosis (2000-2006) ranged from 0.34% to 1.0%, according to the region. A slowly decreasing trend was observed in non HIV as well as in HIV/AIDS patients in Buenos Aires. In most of these countries, the low coverage of culture methods, especially of those including pyruvate-containing media, appropriate to isolate M. bovis, contributes to an underestimate of the problem. It was confirmed that BTB in humans exists, even though its relevance seems to be low. Milk pasteurization, sanitary controls to dairy products, and meat inspection at slaughterhouses contribute to the protection of human health. However, occupational aerogenous exposure to TB cattle and their carcasses remains a source of infection in the region.

A web-based laboratory information system to improve quality of care of tuberculosis patients in Peru: functional requirements, implementation and usage statistics.

BACKGROUND: Multi-drug resistant tuberculosis patients in resource-poor settings experience large delays in starting appropriate treatment and may not be monitored appropriately due to an overburdened laboratory system, delays in communication of results, and missing or error-prone laboratory data. The objective of this paper is to describe an electronic laboratory information system implemented to alleviate these problems and its expanding use by the Peruvian public sector, as well as examine the broader issues of implementing such systems in resource-poor settings. METHODS: A web-based laboratory information system "e-Chasqui" has been designed and implemented in Peru to improve the timeliness and quality of laboratory data. It was deployed in the national TB laboratory, two regional laboratories and twelve pilot health centres. Using needs assessment and workflow analysis tools, e-Chasqui was designed to provide for improved patient care, increased quality control, and more efficient laboratory monitoring and reporting. RESULTS: Since its full implementation in March 2006, 29,944 smear microscopy, 31,797 culture and 7,675 drug susceptibility test results have been entered. Over 99% of these results have been viewed online by the health centres. High user satisfaction and heavy use have led to the expansion of e-Chasqui to additional institutions. In total, e-Chasqui will serve a network of institutions providing medical care for over 3.1 million people. The cost to maintain this system is approximately US$0.53 per sample or 1% of the National Peruvian TB program's 2006 budget. CONCLUSION: Electronic laboratory information systems have a large potential to improve patient care and public health monitoring in resource-poor settings. Some of the challenges faced in these settings, such as lack of trained personnel, limited transportation, and large coverage areas, are obstacles that a well-designed system can overcome. e-Chasqui has the potential to provide a national TB laboratory network in Peru. Furthermore, the core functionality of e-Chasqui as been implemented in the open source medical record system OpenMRS http://www.openmrs.org for other countries to use.

Assessing effects of the e-Chasqui laboratory information system on accuracy and timeliness of bacteriology results in the Peruvian tuberculosis program.

We created a web-based laboratory information system, e-Chasqui to connect public laboratories to health centers to improve communication and analysis. After one year, we performed a pre and post assessment of communication delays and found that e-Chasqui maintained the average delay but eliminated delays of over 60 days. Adding digital verification maintained the average delay, but should increase accuracy. We are currently performing a randomized evaluation of the impacts of e-Chasqui.

Detección rápida de resistencia a drogas en Mycobacterium tuberculosis mediante PCR-SSCP y PCR-heteroduplex / Quick detection of Mycobacterium tuberculosis drug resistance using PCR-SSCP and PCR-heteroduplex

Objetivo: Detectar tempranamente la susceptibilidad a las drogas antituberculosas rifampicina e isoniacida mediante PCR y electroforesis conformacional. Materiales y métodos: Se implementaron dos ensayos de amplificación de los genes rpoB y katG y mediante Heteroduplex y SSCP se determino la susceptibilidad antituberculosa de 31 muestras clínicas procedentes de pacientes con diagnóstico de tuberculosis pulmonar baciloscopia positiva. La caracterización fenotípica de la susceptibilidad, se realizó empleando el método de las proporciones. Resultados: Los ensayos de PCR detectaron hasta 2,5 pg de ADN genómico de M. tuberculosis; no amplificando ADN de otras micobacterias y bacterias comunes de la flora bucal. Se encontró una concordancia general entre la detección molecular y convencional de la susceptibilidad a rifampicina e isoniacida de 96.7 por ciento y 83,9 por ciento (p<0,05), respectivamente. Sin embargo sólo en pacientes con antecedente de tratamiento se presentó una concordancia del 100 por ciento y 90,9 por ciento (p<0,05) para rifampicina e isoniacida, respectivamente. Además, este sistema de detección de resistencia puede emitir resultados 48 horas después de la recepción de la muestra clínica. Conclusiones: Estos sistemas se presentan como una excelente alternativa para la identificación temprana de pacientes infectados con bacilos de M. tuberculosis drogoresistentes. Potencialmente se podrán dirigir óptimos y oportunos esquemas terapéuticos que contribuiran con el control y prevención de la transmisión de cepas multidrogo-resistentes que afectan en gran medidad a la salud pública d nuestro país

Resistencia primaria del Mycobacterium tuberculosis a los medicamentos antituberculosos en el Perú (1993 - 1994) / Primary resistence of Mycobacterium tuberculosis the antituberculous drugs in Peru

Entre Octubre 1993 y Setiembre de 1994 se estudiaron 477 aislamientos de mycobacterium tuberculosis obtenidos del esputo de pacientes que refirieron nunca haber recibido tratamiento. El objetivo fue determinar las cifras de resistencia inicial a medicamentos antituberculosos en momentos en que la tasa de morbilidad correspondía a 250 por 100.000 habitantes. El estudio se realizó en el Laboratorio de Referencia de Micobacterias del Instituto nacional de Salud en Lima, Perú. Todo paciente cuyo esputo fue estudiado, fue encuestado por personal de salud de los establecimientos del Ministerio de Salud, los pacientes habían asistido por tos de dos semanas de evolución. Se utilizó el medio de Ogawa para el aislamiento del Mycobacterium tuberculosis y el medio de Lowenstein Jensen para los estudios de sensibilidad a medicamentos antituberculosos. La tipificación de la micobacteria se basó en características culturales y bioquímicas de cada cultivo. Se encontró 65 (13.6 por ciento) aislamientos con resistencia a uno o más medicamentos antituberculosos. El análisis por medicamento demostró resistencia de 7.3 por ciento a estreptomicina, 5.7 por ciento a isoniacida, 0.8 por ciento a rifampicina, 0.2 por ciento a etambutol y ninguna resistencia a la pirazinamida. El estudio demostró que la cifra global de resistencia a la isoniacida, estreptomicina y rifampicina son altas en la población estudiada. Los resultados justifican el uso de cuatro drogas durante los dos primeros meses de tratamiento antituberculoso en el Perú.

Resistencia inicial del M. tuberculosis a las drogas antituberculosas (1988-1989) / Initial resistance of M. tuberculosis to antituberculous drugs (1988-1989)

Entre 1988-1989, se estudiaron 86 cepas de M. tuberculosis aisladas de esputos de pacientes virgenes al tratamiento y provenientes de las Unidades Departamentales de salud de Lima, Callao y La Libertad. el objetivo fue determinar las cifras de resistencia inicial a drogas antituberculosas en areas del Perú donde las prevalencias de tuberculosis es poco mas del 50 por ciento del total nacional. En promedio se encontro una resistencia inicial para una o mas drogas antituberculosas de 30.2 por ciento. Los porcentajes mas altos de resistencia se encontraron en la provincia del Callao(43.7 por ciento), seguida de Lima (30.3 por ciento) y La Libertad (9.5 por ciento). El analisis de resistencia a una sola droga muestra una RI de 17.4 por ciento para estreptomicina, 3.5 por ciento para isoniacida, 2.3 por ciento para etambutol y 1.2 por ciento para Rifampicina; sin embargo estos porcentages de resistencia aumentan cuando la droga se le considera asociada a otras drogas. Asi, corresponde 22 por ciento a estreptomicina, 9.3 por ciento a isoniacida, 5.8 por ciento a rifampicina. Los resultados demuestran que la resistencia inicial a una o mas drogas es alta en la población estudiada. Se sugiere la necesidad actual de realizar estudios similares a nivel nacional en pacientes con tuberculosis pulmonar