[An emerging problem: heteroresistance in Mycobacterium tuberculosis]

Mixed infection by Mycobacterium tuberculosis (Mtb) consists in the simultaneous coexistence in the same patient of two different strains of Mtb or 2 different variants of the same strain. When one of the variants selects for resistance mutations, it is called monoclonal heteroresistance (HTR); if there are 2 different strains, one sensitive and one resistant (or with different resistance patterns), it is called polyclonal HTR. Three cases of HIV/AIDS patients are presented, all with repeated treatment adherence problems, in whom monoclonal HTR was diagnosed through Mtb complete genomic sequentiation with the coexistence of two variants of the same strain isolated from samples from lung and lymph nodes, with different resistance profiles in each case. It is important to consider the possibility of HTR, especially in patients with multiple previous therapeutic attempts and high bacillary populations, such as in advanced AIDS, since this situation potentially compromises treatment results by coexisting sensitive and resistant variants of a strain (or strains).

Evidence-based Definition for Extensively Drug-resistant Tuberculosis

RATIONALE

Until 2020, extensively drug-resistant tuberculosis (XDR-TB) was defined as resistance to rifampicin and isoniazid (multidrug-resistant tuberculosis, MDR-TB), any fluoroquinolone (FQ) and any second-line injectable drug (SLID). In 2019 the World Health Organization issued new recommendations for managing patients with drug-resistant tuberculosis, substantially limiting the role of SLID in MDR-TB treatment and thus putting that XDR-TB definition into question.

OBJECTIVE

To propose an up-to-date definition for XDR-TB.

METHODS

We used a large dataset to assess treatment outcomes for MDR-TB patients exposed to any type of longer regimen. We included patients with bacteriologically confirmed MDR-TB and known FQ and SLID resistance results. We did logistic regression to estimate adjusted odds ratios (aORs) for unfavourable treatment outcome (failure, relapse, death, loss-to-follow-up) by resistance pattern (FQ, SLID) and Group A drug use (moxifloxacin/levofloxacin, linezolid, bedaquiline).

MEASUREMENTS AND MAIN RESULTS

We included 11,666 patients with MDR-TB; 4653 (39.9%) had an unfavourable treatment outcome. Resistance to FQs increased the odds of an unfavourable treatment outcome (aOR 1.91; 95% confidence interval [95%CI] 1.63-2.23). Administration of bedaquiline and/or linezolid improved treatment outcomes regardless of resistance to FQ and/or SLID. Among XDR-TB patients, compared to persons receiving no Group A drug, aORs for unfavourable outcome were 0.37 (95%CI 0.20-0.69) with linezolid only, 0.40 (95%CI 0.21-0.77) with bedaquiline only, and 0.21 (95%CI 0.12-0.38) with both.

CONCLUSIONS

Our study supports a new definition of XDR-TB as MDR plus additional resistance to FQ plus bedaquiline and/or linezolid, and helps assess the adequacy of this definition for surveillance and treatment choice.NOTE: This article has been updated on July 16, 2021. When it was initially posted on June 9, 2021, the name of one of the coauthors, Dr. Christian Lienhardt, was inadvertently omitted. This version includes Dr. Lienhardt's affilations and contributions; the affiliations have therefore been renumbered.

Neutrophil autophagy during human active tuberculosis is modulated by SLAMF1

Neutrophils infected with Mycobacterium tuberculosis (Mtb) predominate in tuberculosis patients' lungs. Neutrophils phagocytose the pathogen, but the mechanism of pathogen elimination is controversial. Macroautophagy/autophagy, a crucial mechanism for several neutrophil functions, can be modulated by immunological mediators. The costimulatory molecule SLAMF1 can act as a microbial sensor in macrophages being also able to interact with autophagy-related proteins. Here, we demonstrate for the first time that human neutrophils express SLAMF1 upon Mtb-stimulation. Furthermore, SLAMF1 was found colocalizing with LC3B⁺ vesicles, and activation of SLAMF1 increased neutrophil autophagy induced by Mtb. Finally, tuberculosis patients' neutrophils displayed reduced levels of SLAMF1 and lower levels of autophagy against Mtb as compared to healthy controls. Altogether, these results indicate that SLAMF1 participates in neutrophil autophagy during active tuberculosis.Abbreviations: AFB: acid-fast bacilli; BafA1: bafilomycin A₁; CLL: chronic lymphocytic leukemia; DPI: diphenyleneiodonium; EVs: extracellular vesicles; FBS: fetal bovine serum; HD: healthy donors; HR: high responder (tuberculosis patient); IFNG: interferon gamma; IL1B: interleukin 1 beta; IL17A: interleukin 17A; IL8: interleukin 8; LR: low responder (tuberculosis patient); mAb: monoclonal antibody; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MAPK1/ERK2: mitogen-activated protein kinase 1; MAPK14/p38: mitogen-activated protein kinase 14; Mtb: Mycobacterium tuberculosis; Mtb-Ag: Mycobacterium tuberculosis, Strain H37Rv, whole cell lysate; NETs: neutrophils extracellular traps; PPD: purified protein derivative; ROS: reactive oxygen species; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; SLAMF1: signaling lymphocytic activation molecule family member 1; TB: tuberculosis; TLR: toll like receptor.

Fatty acid oxidation of alternatively activated macrophages prevents foam cell formation, but Mycobacterium tuberculosis counteracts this process via HIF-1α activation

The ability of Mycobacterium tuberculosis (Mtb) to persist inside host cells relies on metabolic adaptation, like the accumulation of lipid bodies (LBs) in the so-called foamy macrophages (FM), which are favorable to Mtb. The activation state of macrophages is tightly associated to different metabolic pathways, such as lipid metabolism, but whether differentiation towards FM differs between the macrophage activation profiles remains unclear. Here, we aimed to elucidate whether distinct macrophage activation states exposed to a tuberculosis-associated microenvironment or directly infected with Mtb can form FM. We showed that the triggering of signal transducer and activator of transcription 6 (STAT6) in interleukin (IL)-4-activated human macrophages (M(IL-4)) prevents FM formation induced by pleural effusion from patients with tuberculosis. In these cells, LBs are disrupted by lipolysis, and the released fatty acids enter the β-oxidation (FAO) pathway fueling the generation of ATP in mitochondria. Accordingly, murine alveolar macrophages, which exhibit a predominant FAO metabolism, are less prone to become FM than bone marrow derived-macrophages. Interestingly, direct infection of M(IL-4) macrophages with Mtb results in the establishment of aerobic glycolytic pathway and FM formation, which could be prevented by FAO activation or inhibition of the hypoxia-inducible factor 1-alpha (HIF-1α)-induced glycolytic pathway. In conclusion, our results demonstrate that Mtb has a remarkable capacity to induce FM formation through the rewiring of metabolic pathways in human macrophages, including the STAT6-driven alternatively activated program. This study provides key insights into macrophage metabolism and pathogen subversion strategies.

Tuberculosis is a deadly disease caused by Mycobacterium tuberculosis. Although progress has been made in tuberculosis control, there are unexplored aspects of how the immune system deals with the pathogen that need to be addressed. M. tuberculosis primarily lives in macrophages, immune cells which can destroy mycobacteria. In spite of the multiple microbicidal properties, the bacterium still manipulates the metabolism of macrophages, reflected in the accumulation lipid droplets and consequent differentiation into foamy macrophages. These lipid-laden macrophages constitute a favorable niche for the bacteria to persist hidden from our immune defense. Macrophages are classified into different programs depending on how they are activated by environmental signals, ranging from classically (microbicidal/inflammatory) to alternatively (tissue remodeling/repair/growth) activated spectrum extremes. We found that, unlike other programs, alternatively activated macrophages are reluctant to accumulate lipid droplets due to the signal transducer and activator of transcription 6 (STAT6), which promotes the degradation of those lipids. Notwithstanding, M. tuberculosis counteracts lipolysis by rewiring the metabolism of alternatively activated macrophages towards the accumulation of lipid droplets via the activation of the hypoxia-inducible factor 1-alpha (HIF-1α). Therefore, this study contributes to the better understanding of how bacillus shifts the metabolism of macrophages, which can be crucial to therapeutic purposes.

Mortality in adults with multidrug-resistant tuberculosis and HIV by antiretroviral therapy and tuberculosis drug use: an individual patient data meta-analysis

BACKGROUND

HIV-infection is associated with increased mortality during multidrug-resistant tuberculosis treatment, but the extent to which the use of antiretroviral therapy (ART) and anti-tuberculosis medications modify this risk are unclear. Our objective was to evaluate how use of these treatments altered mortality risk in HIV-positive adults with multidrug-resistant tuberculosis.

METHODS

We did an individual patient data meta-analysis of adults 18 years or older with confirmed or presumed multidrug-resistant tuberculosis initiating tuberculosis treatment between 1993 and 2016. Data included ART use and anti-tuberculosis medications grouped according to WHO effectiveness categories. The primary analysis compared HIV-positive with HIV-negative patients in terms of death during multidrug-resistant tuberculosis treatment, excluding those lost to follow up, and was stratified by ART use. Analyses used logistic regression after exact matching on country World Bank income classification and drug resistance and propensity-score matching on age, sex, geographic site, year of multidrug-resistant tuberculosis treatment initiation, previous tuberculosis treatment, directly observed therapy, and acid-fast-bacilli smear-positivity to obtain adjusted odds ratios (aORs) and 95% CIs. Secondary analyses were conducted among those with HIV-infection.

FINDINGS

We included 11 920 multidrug-resistant tuberculosis patients. 2997 (25%) were HIV-positive and on ART, 886 (7%) were HIV-positive and not on ART, and 1749 (15%) had extensively drug-resistant tuberculosis. By use of HIV-negative patients as reference, the aOR of death was 2·4 (95% CI 2·0-2·9) for all patients with HIV-infection, 1·8 (1·5-2·2) for HIV-positive patients on ART, and 4·2 (3·0-5·9) for HIV-positive patients with no or unknown ART. Among patients with HIV, use of at least one WHO Group A drug and specific use of moxifloxacin, levofloxacin, bedaquiline, or linezolid were associated with significantly decreased odds of death.

INTERPRETATION

Use of ART and more effective anti-tuberculosis drugs is associated with lower odds of death among HIV-positive patients with multidrug-resistant tuberculosis. Access to these therapies should be urgently pursued.

FUNDING

American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Treatment correlates of successful outcomes in pulmonary multidrug-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Treatment outcomes for multidrug-resistant tuberculosis remain poor. We aimed to estimate the association of treatment success and death with the use of individual drugs, and the optimal number and duration of treatment with those drugs in patients with multidrug-resistant tuberculosis.

METHODS

In this individual patient data meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library to identify potentially eligible observational and experimental studies published between Jan 1, 2009, and April 30, 2016. We also searched reference lists from all systematic reviews of treatment of multidrug-resistant tuberculosis published since 2009. To be eligible, studies had to report original results, with end of treatment outcomes (treatment completion [success], failure, or relapse) in cohorts of at least 25 adults (aged >18 years). We used anonymised individual patient data from eligible studies, provided by study investigators, regarding clinical characteristics, treatment, and outcomes. Using propensity score-matched generalised mixed effects logistic, or linear regression, we calculated adjusted odds ratios and adjusted risk differences for success or death during treatment, for specific drugs currently used to treat multidrug-resistant tuberculosis, as well as the number of drugs used and treatment duration.

FINDINGS

Of 12 030 patients from 25 countries in 50 studies, 7346 (61%) had treatment success, 1017 (8%) had failure or relapse, and 1729 (14%) died. Compared with failure or relapse, treatment success was positively associated with the use of linezolid (adjusted risk difference 0·15, 95% CI 0·11 to 0·18), levofloxacin (0·15, 0·13 to 0·18), carbapenems (0·14, 0·06 to 0·21), moxifloxacin (0·11, 0·08 to 0·14), bedaquiline (0·10, 0·05 to 0·14), and clofazimine (0·06, 0·01 to 0·10). There was a significant association between reduced mortality and use of linezolid (-0·20, -0·23 to -0·16), levofloxacin (-0·06, -0·09 to -0·04), moxifloxacin (-0·07, -0·10 to -0·04), or bedaquiline (-0·14, -0·19 to -0·10). Compared with regimens without any injectable drug, amikacin provided modest benefits, but kanamycin and capreomycin were associated with worse outcomes. The remaining drugs were associated with slight or no improvements in outcomes. Treatment outcomes were significantly worse for most drugs if they were used despite in-vitro resistance. The optimal number of effective drugs seemed to be five in the initial phase, and four in the continuation phase. In these adjusted analyses, heterogeneity, based on a simulated I² method, was high for approximately half the estimates for specific drugs, although relatively low for number of drugs and durations analyses.

INTERPRETATION

Although inferences are limited by the observational nature of these data, treatment outcomes were significantly better with use of linezolid, later generation fluoroquinolones, bedaquiline, clofazimine, and carbapenems for treatment of multidrug-resistant tuberculosis. These findings emphasise the need for trials to ascertain the optimal combination and duration of these drugs for treatment of this condition.

FUNDING

American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Formation of Foamy Macrophages by Tuberculous Pleural Effusions Is Triggered by the Interleukin-10/Signal Transducer and Activator of Transcription 3 Axis through ACAT Upregulation

The ability of Mycobacterium tuberculosis (Mtb) to persist in its human host relies on numerous immune evasion strategies, such as the deregulation of the lipid metabolism leading to the formation of foamy macrophages (FM). Yet, the specific host factors leading to the foamy phenotype of Mtb-infected macrophages remain unknown. Herein, we aimed to address whether host cytokines contribute to FM formation in the context of Mtb infection. Our approach is based on the use of an acellular fraction of tuberculous pleural effusions (TB-PE) as a physiological source of local factors released during Mtb infection. We found that TB-PE induced FM differentiation as observed by the increase in lipid bodies, intracellular cholesterol, and expression of the scavenger receptor CD36, as well as the enzyme acyl CoA:cholesterol acyl transferase (ACAT). Importantly, interleukin-10 (IL-10) depletion from TB-PE prevented the augmentation of all these parameters. Moreover, we observed a positive correlation between the levels of IL-10 and the number of lipid-laden CD14⁺ cells among the pleural cells in TB patients, demonstrating that FM differentiation occurs within the pleural environment. Downstream of IL-10 signaling, we noticed that the transcription factor signal transducer and activator of transcription 3 was activated by TB-PE, and its chemical inhibition prevented the accumulation of lipid bodies and ACAT expression in macrophages. In terms of the host immune response, TB-PE-treated macrophages displayed immunosuppressive properties and bore higher bacillary loads. Finally, we confirmed our results using bone marrow-derived macrophage from IL-10^-/- mice demonstrating that IL-10 deficiency partially prevented foamy phenotype induction after Mtb lipids exposure. In conclusion, our results evidence a role of IL-10 in promoting the differentiation of FM in the context of Mtb infection, contributing to our understanding of how alterations of the host metabolic factors may favor pathogen persistence.

Mycobacterium tuberculosis multi-drug-resistant strain M induces IL-17+ IFNγ- CD4+ T cell expansion through an IL-23 and TGF-β-dependent mechanism in patients with MDR-TB tuberculosis

We have reported previously that T cells from patients with multi-drug-resistant tuberculosis (MDR-TB) express high levels of interleukin (IL)-17 in response to the MDR strain M (Haarlem family) of Mycobacterium tuberculosis (M. tuberculosis). Herein, we explore the pathways involved in the induction of Th17 cells in MDR-TB patients and healthy tuberculin reactors [purified protein derivative healthy donors (PPD⁺ HD)] by the M strain and the laboratory strain H37Rv. Our results show that IL-1β and IL-6 are crucial for the H37Rv and M-induced expansion of IL-17⁺ interferon (IFN)-γ^- and IL-17⁺ IFN-γ⁺ in CD4⁺ T cells from MDR-TB and PPD⁺ HD. IL-23 plays an ambiguous role in T helper type 1 (Th1) and Th17 profiles: alone, IL-23 is responsible for M. tuberculosis-induced IL-17 and IFN-γ expression in CD4⁺ T cells from PPD⁺ HD whereas, together with transforming growth factor (TGF-β), it promotes IL-17⁺ IFN-γ^- expansion in MDR-TB. In fact, spontaneous and M. tuberculosis-induced TGF-β secretion is increased in cells from MDR-TB, the M strain being the highest inducer. Interestingly, Toll-like receptor (TLR)-2 signalling mediates the expansion of IL-17⁺ IFN-γ^- cells and the enhancement of latency-associated protein (LAP) expression in CD14⁺ and CD4⁺ T cells from MDR-TB, which suggests that the M strain promotes IL-17⁺ IFN-γ^- T cells through a strong TLR-2-dependent TGF-β production by antigen-presenting cells and CD4⁺ T cells. Finally, CD4⁺ T cells from MDR-TB patients infected with MDR Haarlem strains show higher IL-17⁺ IFN-γ^- and lower IL-17⁺ IFN-γ⁺ levels than LAM-infected patients. The present findings deepen our understanding of the role of IL-17 in MDR-TB and highlight the influence of the genetic background of the infecting M. tuberculosis strain on the ex-vivo Th17 response.

Impact of HIV co-infection on the evolution and transmission of multidrug-resistant tuberculosis

The tuberculosis (TB) epidemic is fueled by a parallel Human Immunodeficiency Virus (HIV) epidemic, but it remains unclear to what extent the HIV epidemic has been a driver for drug resistance in Mycobacterium tuberculosis (Mtb). Here we assess the impact of HIV co-infection on the emergence of resistance and transmission of Mtb in the largest outbreak of multidrug-resistant TB in South America to date. By combining Bayesian evolutionary analyses and the reconstruction of transmission networks utilizing a new model optimized for TB, we find that HIV co-infection does not significantly affect the transmissibility or the mutation rate of Mtb within patients and was not associated with increased emergence of resistance within patients. Our results indicate that the HIV epidemic serves as an amplifier of TB outbreaks by providing a reservoir of susceptible hosts, but that HIV co-infection is not a direct driver for the emergence and transmission of resistant strains.

[Phthalate exposure in the neonatal intensive care unit]

There are growing concerns on long-term health consequences, notably on fertility rates, of plasticizers such as phthalates. While di(2-ethylhexyl)phthalate (DEHP) is currently used in several medical devices, newborns in the neonatal intensive care unit are both more exposed and more vulnerable to DEHP. The objectives of this study were to identify, count, and describe possible sources of DEHP in a neonatal care unit. Our method consisted in the listing and the inspection of the information on packaging, complemented by contact with manufacturers when necessary. According to the results, 6% of all products and 10% of plastic products contained some DEHP; 71% of these involved respiratory support devices. A vast majority of the items showed no information on the content of DEHP. Further research is needed, particularly to determine the effects of such an early exposure and to study and develop safer alternatives.

[Job's syndrome and miliary tuberculosis]

The hyper Immunoglobulin E syndrome, also known as Job's syndrome, is a rare primary immunodeficiency, its mechanisms of inheritance maybe recessive or dominant autosomal. It is characterized by high levels of IgE, eosinophilia, skin abscesses, eczema, chronic mucocutaneous candidiasis and recurrent pulmonary infections all of which contribute to the development of pneumatoceles and bronchiectasis. The most frequently isolated bacteria is Staphylococcus aureus. Currently, despite the highest survival of patients, lymphomas and other opportunistic infections have been reported. There are few reports of patients with Mycobacterium tuberculosis infection associated with hyper IgE syndrome. Therefore it is relevant that we report a case history of a patient with pulmonary tuberculosis, presenting miliary tuberculosis and severe respiratory compromise, who responded positively to standard anti-tuberculous treatment with first line drugs.

First Report of Homothallic Isolates of Phytophthora infestans in Commercial Potato Crops (Solanum tuberosum) in the Toluca Valley, Mexico

Phytophthora infestans causes severe symptoms of wilt disease on potato crops (Solanum tuberosum) in the Toluca Valley (Mexico) despite the use of fungicides. P. infestans oospores produced by sexual reproduction can survive in the soil for many years, resisting harsh environments. In many agroecosystems, oospores germinate in the beginning of a season, which represents the initial inoculum for epidemics. The sexual cycle of the pathogen allows the generation of recombinant genotypes that can be more pathogenic or even resistant to chemicals. This paper presents a study of 20 isolates of P. infestans collected from potato crops in the Toluca Valley within the municipality of Zinacantepec (Mexico State). Isolates were obtained from potato foliar infected tissues. The pathogen was confirmed as P. infestans on the basis of morphological characters (1). Sporangia were caducous, ovoid, limoniform, semipapillate, and were 28.4 ± 1.3 × 17.6 ± 1.2 μm (height × width). Mycelium was coenocytic with hyphal diameter of 5 to 8 μm. Five isolates were collected in 2011, and 15 in 2012. Isolates were transferred by hyphal tip to culture medium plates with V8 juice agar and incubated at 19°C. All the isolates were mated to determine the mating type with the reference isolates J104 (A1) and J204 (A2), which were provided by the Michoacana University of San Nicolás de Hidalgo (Mx). Isolates that produced oospores with both A1 and A2 testers (J104 and J204) and in a single culture were designated homothallic. Results show that two out of the five isolates collected in 2011 were homothallic and the other three were type A1. Regarding the 15 isolates collected in 2012, six were typed as A1, five as A2, and four were homothallic. The heterothallic isolates only produce oospores when mated with the opposite mating type. The homothallic isolates possessed the ability to act as A1 and A2 during heterothallic mating and were found capable of producing sexual structures (oogonia and amphigynous antheridia) in a single culture, a phenomenon not observed in isolates that are strictly A1 or A2. Oospores formed were aplerotic and measured 32.2 ± 3.3 μm in diameter. Single-sporangium progeny were produced from the six homothallic isolates to be analyzed to confirm the occurrence of the self-fertility. Assessment of 48 single-sporangium progeny from the homothallic isolates resulted in 22 homothallic, 12 A1, 10 A2, and four sterile. These results differ from those found by Grünwald et al. (3), who conducted a study with isolates collected from the Toluca Valley region in 1997 and 1998, finding a 1:1 frequency between compatibility types A1 and A2. Fernandez et al. (2) studied a broad population of 27 isolates from potato crops in the state of Michoacán (Mx), and found two homothallic isolates among heterothallic isolates; the ratio was 1:1. Also, homothallic isolates have been found in Spain and China (4). To our knowledge, this is the first report of the occurrence of homothallic P. infestans isolates in commercial potato crops (S. tuberosum) in the Toluca Valley, Mexico. References: (1) D. C. Erwin and O. K. Ribeiro, Page 346 in: Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN, 1996. (2) S. P. Fernández et al. Rev. Mexicana Fitopatol. 23:191, 2005. (3) N. J. Grünwald et al. Phytopathology 91:883, 2001. (4) M. Han et al. J. Eukaryotic Microbiol. 60:79, 2013.

Drug resistance beyond extensively drug-resistant tuberculosis: individual patient data meta-analysis

The broadest pattern of tuberculosis (TB) drug resistance for which a consensus definition exists is extensively drug-resistant (XDR)-TB. It is not known if additional drug resistance portends worsened patient outcomes. This study compares treatment outcomes of XDR-TB patients with and without additional resistance in order to explore the need for a new definition. Individual patient data on XDR-TB outcomes were included in a meta-analysis comparing outcomes between XDR alone and three nonmutually exclusive XDR-TB patient groups: XDR plus resistance to all the second-line injectables (sli) and capreomycin and kanamycin/amikacin (XDR+2sli) XDR plus resistance to second-line injectables and to more than one group 4 drug, i.e. ethionamide/protionamide, cycloserine/terizidone or para-aminosalicylic acid (XDR+sliG4) and XDR+sliG4 plus resistance to ethambutol and/or pyrazinamide (XDR+sliG4EZ). Of 405 XDR-TB cases, 301 were XDR alone, 68 XDR+2sli, 48 XDR+sliG4 and 42 XDR+sliG4EZ. In multivariate analysis, the odds of cure were significantly lower in XDR+2sli (adjusted OR 0.4, 95% CI 0.2-0.8) compared to XDR alone, while odds of failure and death were higher in all XDR patients with additional resistance (adjusted OR 2.6-2.8). Patients with additional resistance beyond XDR-TB showed poorer outcomes. Limitations in availability, accuracy and reproducibility of current drug susceptibility testing methods preclude the adoption of a useful definition beyond the one currently used for XDR-TB.

IL-9-producing cells promote Th1 responses against Mycobacterium tuberculosis. (P3015)

IFNγ-secreting cells are critical in the defense against M. tuberculosis (Mtb) infection, but other cells might be required to eradicate the pathogen. IL-9-producing cells were reported to be involved in inflammation and immune diseases, but their role during tuberculosis remains to be clarified. Here we analyzed the involvement of IL-9-secreting cells in the immunity of patients with active disease. We demonstrated that Mtb induced a marked expansion of CD4 IL-9+ cells in peripheral blood from tuberculosis patients. After antigen stimulation, patients with robust Th1 responses to Mtb (high responders) produced higher amounts of IL-9 compared to those with weak Th1 responses (low responders) and a direct significant correlation between IL-9 and IFNγ production against Mtb was detected. To investigate the role of the IL-9 secreted by those lymphocytes, we inhibited IL-9 expression with siRNA, which significantly diminished the production of IFNγ against Mtb. Addition of IL-9 markedly increased the secretion of IFNγ against Mtb, even in low responders. Furthermore, treatment with IL-9 inhibited Mtb-induced apoptosis of IFNγ+ cells, enhancing the survival of the cells. Finally, by studying the effect of neutralizing IL-9 antibodies on polarized Th9 cells, we confirmed that IL-9 participates in the up-regulation of IFNγ production against Mtb. Thus, our results indicate that IL-9 enhances Th1 responses during tuberculosis promoting the cell-mediated immunity to the pathogen.

HIV infection and geographically bound transmission of drug-resistant tuberculosis, Argentina

Disease trends are driven by HIV co-infection and transmission of a few strains within narrow geographic niches.

During 2003–2009, the National Tuberculosis (TB) Laboratory Network in Argentina gave 830 patients a new diagnosis of multidrug-resistant (MDR) TB and 53 a diagnosis of extensively drug- resistant (XDR) TB. HIV co-infection was involved in nearly one third of these cases. Strain genotyping showed that 7 major clusters gathered 56% of patients within restricted geographic areas. The 3 largest clusters corresponded to epidemic MDR TB strains that have been undergoing transmission for >10 years. The indigenous M strain accounted for 29% and 40% of MDR and XDR TB cases, respectively. Drug-resistant TB trends in Argentina are driven by spread of a few strains in hotspots where the rate of HIV infection is high. To curb transmission, the national TB program is focusing stringent interventions in these areas by strengthening infection control in large hospitals and prisons, expediting drug resistance detection, and streamlining information-sharing systems between HIV and TB programs.

Difficult clinical management of anti-tuberculosis DRESS syndrome

We describe 11 cases of anti-tuberculosis DRESS (drug-related rash with eosinophilia and systemic symptoms) syndrome, a potentially serious complication of treatment that led to interruption of treatment for prolonged periods, systemic corticosteroid use and the resumption of treatment with less effective regimens. All patients had rash and toxic hepatitis, one died of multi-organ failure and, contrary to expectations, the evolution of tuberculosis (advanced in most cases) did not progress under corticosteroid treatment. The drug most frequently involved was rifampicin, while retreatment schemes included, in most cases, levofloxacin, ethambutol, streptomycin and cycloserine.

First Report of Fusarium verticillioides Causing Stalk and Root Rot of Sorghum in Spain

Sweet sorghum (Sorghum bicolor L.) is considered one of the most promising crops for bioethanol production in many countries and is a focus of bioenergy research worldwide. In July 2011, plants of the sweet sorghum cv. Suchro 506 in Oropesa (Toledo, Spain, 40.048577°N, 5.360298°W) (European Datum 1950 UTM zone 30 N) were observed with severe wilting. Upon examination, the lower internodes were found to be straw colored. When the plant was split, the internal pith was reddish, soft, and disintegrating. Small pieces of symptomatic stems and roots were surface disinfected in sodium hypochlorite (0.5% wt/vol) for 2 min and air dried. The sections were then placed on either PDA (potato dextrose agar) medium or Komada agar and incubated for 5 days at 25°C. Isolations from diseased stem and root tissue consistently yielded Fusarium verticillioides (Sacc.) Nirenberg (3). The small, hyaline, mostly single-celled, oval to club-shaped microconidia of F. verticillioides were produced in long catenate chains arising from monophialides. PCR amplification of the ITS1-5.8S-ITS2 was performed using the primers and protocols described elsewhere (4) and the fragments obtained were subsequently sequenced in both directions. Sequences were deposited in the EMBL Sequence Database (Accession Nos. HE652878, HE652879, HE652880, and HE652881). Four of the recovered F. verticilliodes isolates were tested in pathogenicity assays. One-week-old cultures of each isolate were homogenized in 400 ml of sterile water and 200 ml were used to inoculate water-growth-chamber-grown plants in 500-ml pots. Two pots each with three plants of cv. Suchro 506 were inoculated for each isolate. Water with sterile PDA was used as a control. All plants were kept at 20 to 25°C under a photoperiod of 14 h at 12,000 lux. After 21 days, above- and belowground parts were dried for 24 h at 60°C. Total length and dry weight of both sections were obtained. Inoculated plants produced root rot symptoms characteristic of F. verticillioides with dark red discolorations of the cortex of seedling roots (1), whereas the plants watered with water containing only PDA did not produce symptoms. Inoculated plants also had a decrease in dry weight for above- and belowground sections (P = 0.05) compared with the control with 43 and 47% reductions, respectively. The length of aerial parts was approximately 5% less in inoculated plants compared with control plants. F. verticillioides was reisolated from all inoculated plants. Sorghum stalk and root rot caused by F. verticillioides has been reported in different countries including India (2) and the United States (3). To our knowledge, this is the first report of F. verticillioides causing stalk and root rot of sorghum in Spain. An increase of production of this crop is expected to meet targets of the renewable energy share in Spain and any disease compromising yield may be a threat to this endeavour. References: (1) R. A. Frederiksen and G. N. Odvody. Compendium of Sorghum Diseases. The American Phytopathological Society. St. Paul, MN, 2000. (2) N. N. Khune et al. Indian Phytopathol. 37:316, 1984. (3) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

IL-17 and IFN-γ expression in lymphocytes from patients with active tuberculosis correlates with the severity of the disease

Th1 lymphocytes are crucial in the immune response against Mycobacterium tuberculosis. Nevertheless, IFN-γ alone is not sufficient in the complete eradication of the bacteria, suggesting that other cytokines might be required for pathogen removal. Th17 cells have been associated with M. tuberculosis infection, but the role of IL-17-producing cells in human TB remains to be understood. Therefore, we investigated the induction and regulation of IFN-γ and IL-17 during the active disease. TB patients were classified as High and Low Responder individuals according to their T cell responses against the antigen, and cytokine expression upon M. tuberculosis stimulation was investigated in peripheral blood and pleural fluid. Afterwards, the potential correlation among the proportions of cytokine-producing cells and clinical parameters was analyzed. In TB patients, M. tuberculosis induced IFN-γ and IL-17, but in comparison with BCG-vaccinated healthy donors, IFN-γ results were reduced significantly, and IL-17 was markedly augmented. Moreover, the main source of IL-17 was represented by CD4(+)IFN-γ(+)IL-17(+) lymphocytes, a Th1/Th17 subset regulated by IFN-γ. Interestingly, the ratio of antigen-expanded CD4(+)IFN-γ(+)IL-17(+) lymphocytes, in peripheral blood and pleural fluid from TB patients, was correlated directly with clinical parameters associated with disease severity. Indeed, the highest proportion of CD4(+)IFN-γ(+)IL-17(+) cells was detected in Low Responder TB patients, individuals displaying severe pulmonary lesions, and longest length of disease evolution. Taken together, the present findings suggest that analysis of the expansion of CD4(+)IFN-γ(+)IL-17(+) T lymphocytes in peripheral blood of TB patients might be used as an indicator of the clinical outcome in active TB.

Multidrug resistant pulmonary tuberculosis treatment regimens and patient outcomes: an individual patient data meta-analysis of 9,153 patients

BACKGROUND

Treatment of multidrug resistant tuberculosis (MDR-TB) is lengthy, toxic, expensive, and has generally poor outcomes. We undertook an individual patient data meta-analysis to assess the impact on outcomes of the type, number, and duration of drugs used to treat MDR-TB.

METHODS AND FINDINGS

Three recent systematic reviews were used to identify studies reporting treatment outcomes of microbiologically confirmed MDR-TB. Study authors were contacted to solicit individual patient data including clinical characteristics, treatment given, and outcomes. Random effects multivariable logistic meta-regression was used to estimate adjusted odds of treatment success. Adequate treatment and outcome data were provided for 9,153 patients with MDR-TB from 32 observational studies. Treatment success, compared to failure/relapse, was associated with use of: later generation quinolones, (adjusted odds ratio [aOR]: 2.5 [95% CI 1.1-6.0]), ofloxacin (aOR: 2.5 [1.6-3.9]), ethionamide or prothionamide (aOR: 1.7 [1.3-2.3]), use of four or more likely effective drugs in the initial intensive phase (aOR: 2.3 [1.3-3.9]), and three or more likely effective drugs in the continuation phase (aOR: 2.7 [1.7-4.1]). Similar results were seen for the association of treatment success compared to failure/relapse or death: later generation quinolones, (aOR: 2.7 [1.7-4.3]), ofloxacin (aOR: 2.3 [1.3-3.8]), ethionamide or prothionamide (aOR: 1.7 [1.4-2.1]), use of four or more likely effective drugs in the initial intensive phase (aOR: 2.7 [1.9-3.9]), and three or more likely effective drugs in the continuation phase (aOR: 4.5 [3.4-6.0]).

CONCLUSIONS

In this individual patient data meta-analysis of observational data, improved MDR-TB treatment success and survival were associated with use of certain fluoroquinolones, ethionamide, or prothionamide, and greater total number of effective drugs. However, randomized trials are urgently needed to optimize MDR-TB treatment. Please see later in the article for the Editors' Summary.

WHO guidelines for the programmatic management of drug-resistant tuberculosis: 2011 update

The production of guidelines for the management of drug-resistant tuberculosis (TB) fits the mandate of the World Health Organization (WHO) to support countries in the reinforcement of patient care. WHO commissioned external reviews to summarise evidence on priority questions regarding case-finding, treatment regimens for multidrug-resistant TB (MDR-TB), monitoring the response to MDR-TB treatment, and models of care. A multidisciplinary expert panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to develop recommendations. The recommendations support the wider use of rapid drug susceptibility testing for isoniazid and rifampicin or rifampicin alone using molecular techniques. Monitoring by sputum culture is important for early detection of failure during treatment. Regimens lasting ≥ 20 months and containing pyrazinamide, a fluoroquinolone, a second-line injectable drug, ethionamide (or prothionamide), and either cycloserine or p-aminosalicylic acid are recommended. The guidelines promote the early use of antiretroviral agents for TB patients with HIV on second-line drug regimens. Systems that primarily employ ambulatory models of care are recommended over others based mainly on hospitalisation. Scientific and medical associations should promote the recommendations among practitioners and public health decision makers involved in MDR-TB care. Controlled trials are needed to improve the quality of existing evidence, particularly on the optimal composition and duration of MDR-TB treatment regimens.

Comparative study of the pathogenicity of seabed isolates of Fusarium equiseti and the effect of the composition of the mineral salt medium and temperature on mycelial growth

The pathogenicity of seven strains of Fusarium equiseti isolated from seabed soil was evaluated on different host plants showing pre and post emergence damage. Radial growth of 27 strains was measured on culture media previously adjusted to different osmotic potentials with either KCl or NaCl (-1.50 to -144.54 bars) at 15°, 25° and 35° C. Significant differences and interactive effects were observed in the response of mycelia to osmotic potential and temperature.

Fungal microbiota from rain water and pathogenicity of Fusarium species isolated from atmospheric dust and rainfall dust

In order to determine the presence of Fusarium spp. in atmospheric dust and rainfall dust, samples were collected during September 2007, and July, August, and October 2008. The results reveal the prevalence of airborne Fusarium species coming from the atmosphere of the South East coast of Spain. Five different Fusarium species were isolated from the settling dust: Fusarium oxysporum, F. solani, F. equiseti, F. dimerum, and F. proliferatum. Moreover, rainwater samples were obtained during significant rainfall events in January and February 2009. Using the dilution-plate method, 12 fungal genera were identified from these rainwater samples. Specific analyses of the rainwater revealed the presence of three species of Fusarium: F. oxysporum, F. proliferatum and F. equiseti. A total of 57 isolates of Fusarium spp. obtained from both rainwater and atmospheric rainfall dust sampling were inoculated onto melon (Cucumis melo L.) cv. Piñonet and tomato (Lycopersicon esculentum Mill.) cv. San Pedro. These species were chosen because they are the main herbaceous crops in Almeria province. The results presented in this work indicate strongly that spores or propagules of Fusarium are able to cross the continental barrier carried by winds from the Sahara (Africa) to crop or coastal lands in Europe. Results show differences in the pathogenicity of the isolates tested. Both hosts showed root rot when inoculated with different species of Fusarium, although fresh weight measurements did not bring any information about the pathogenicity. The findings presented above are strong indications that long-distance transmission of Fusarium propagules may occur. Diseases caused by species of Fusarium are common in these areas. They were in the past, and are still today, a problem for greenhouses crops in Almería, and many species have been listed as pathogens on agricultural crops in this region. Saharan air masses dominate the Mediterranean regions. The evidence of long distance dispersal of Fusarium spp. by atmospheric dust and rainwater together with their proved pathogenicity must be taken into account in epidemiological studies.

First Report of Fusarium proliferatum Causing Rot of Garlic Bulbs in Spain

In October of 2008, decayed garlic bulbs (Allium sativum L. cv. Blancomor de Vallelado) were received from a producer in Segovia, Spain. In November of 2009, similar symptoms were observed on stored bulbs (cvs. Blancomor de Vallelado and Garcua) from each of 30 municipalities in northwest Segovia and Valladolid. A minimum of one sample was collected from 12 localities. Pieces of symptomatic bulbs were surface disinfested for 2 to 3 min in 0.5% NaOCl and transferred to potato dextrose agar (PDA) and Komada's media. Colonies had catenate microconidia and curved macroconidia that were usually three to five septate. Microconidia were club shaped with a flattened base, aseptate, and were produced on both mono- and polyphialides. On the basis of morphological features, the fungus was identified as Fusarium proliferatum (T. Matsushima) Nirenberg (2,3). Pathogenicity tests were conducted with 12 isolates of the fungi following the method of Dugan et al. (1). Each assay with an isolate consisted of six cloves (cv. Blancomor de Vallelado) disinfested in 0.5% NaOCl for 45 s, rinsed with sterile water, and injured to a depth of 4.5 mm with a probe 1 mm in diameter. The wound was filled with PDA colonized by the appropriate isolate. Six cloves for each tested isolate received sterile agar as a control. The cloves were incubated at 25°C for 5 weeks. The test was repeated once with cv. Garcua. All isolates produced water-soaked, tan lesions. An isolate of the fungus was deposited in the collection of the Plant Production Department of the University of Almeria. No fungi were recovered from the control cloves. F. proliferatum has been reported on garlic in the northwestern United States (1) and Serbia (4). To our knowledge, this is the first report of a Fusarium sp. in the section Liseola attacking garlic in Spain. The fungus seems to be well established on this host in Spain. References: (1) F. M. Dugan et al. Phytopathology 155:437, 2007. (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (3) H. Nirenberg et al. Mycologia 90:434, 1998. (4) S. Stankovic et al. Eur. J. Plant Pathol. 118:165, 2007.

[Disease due to Mycobacterium simiae and "Mycobacterium sherrisii" in Argentina]

A revision of mycobacterial disease due to M simiae (n = 4) and "M. sherrisii" (n = 6) identified during an eight-year period is presented. Cases occurred among patients with AIDS (n = 6), previous history of silicosis (n = 2) or tuberculosis (n = 2). One case was lost to follow-up and the remaining nine responded poorly to chemotherapy based on clarithromycin, ethambutol and fluoroquinolones. Five patients died of whom four were HIV-positive, three remained chronic and one was cured. These microorganisms originated 2.1% of mycobacterioses cases detected in an eight-year period. Timely identification of this group of uncommon mycobacteria by molecular methods seems to be clinically relevant in order to warn of difficulties inherent to the treatment. However, the distinction between both closely related microorganisms might not be crucial for case management as no distinctive characteristics were evident among patients affected by M. simiae or "M. sherrisii".

[Adverse drug reactions in multidrug-resistant tuberculosis]

Multidrug-resistant tuberculosis (MDRTB) poses difficulties in diagnosis and treatment, including increased frequency of adverse reactions to antituberculosis drugs (ADRAs), which compromise the effectiveness of treatment. This is specially complicated in the treatment of patients co-infected with HIV which includes the antiretroviral therapy plus the treatment of eventual comorbidities. A total of 121 MDRTB patients, 87 HIV-negative and 34 HIV positive, assisted in the Hospital F. J. Muñiz, Buenos Aires, during the period 2003-2007 were retrospectively studied. The incidence of ADRAs among the two groups of patients was compared. All the patients with adherence to treatment (no more than one abandon, recovered) were included in the study. Antituberculosis drugs used were: ethambutol, pyrazinamide, ofloxacin, moxifloxacin, cycloserine, ethionamide, PAS, streptomycin, kanamycin, amikacin and linezolid. The emergence of ADRAs and the proportion of severe reactions attributed to antituberculosis drugs were similar in both groups: 44.8% in HIV negative and 44.1% in HIV positive, but it was observed an additional 23.5% of adverse reactions to antiretroviral therapy in the second group. There were differences in the type of reactions and time of occurrence between the two groups. One HIV positive patient died of epidermolysis. The proportion of adverse reactions in HIV/AIDS patients increased 50% when those attributed to antiretroviral treatment were included. We conclude that the studied population showed a frequency of ADRAs higher than it would be expected in the treatment of susceptible TB, but there was no difference in its frequency among HIV-negative and positive patients.

Species of Fusarium Isolated from River and Sea Water of Southeastern Spain and Pathogenicity on Four Plant Species

Species of Fusarium were isolated from water samples collected from the Andarax River and coastal sea water of the Mediterranean in Granada and Almería provinces of southeastern Spain. In total, 18 water samples were analyzed from the Andarax River, and 10 species of Fusarium were isolated: Fusarium anthophilum, F. acuminatum, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum, F. solani, and F. sambucinum. In addition, five species were isolated from 33 sea water samples from the Mediterranean Sea: F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum, and F. solani. When considering the samples by their origins, 77.8% of the river water samples yielded at least one species of Fusarium, with F. oxysporum comprising 72.2% of the total isolates. In the case of marine water, 45.5% of the samples yielded at least one species of Fusarium, with F. solani comprising 36.3% of the total isolates. The pathogenicity of 41 isolates representing nine of the species collected from river and sea water during the study was evaluated on barley, kohlrabi, melon, and tomato. Inoculation with F. acuminatum, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum F. solani, and F. sambucinum resulted in pre- and post-emergence damping off. Pathogenicity of Fusarium isolates did not seem to be related to the origin of the isolates (sea water or fresh water). However, the presence of pathogenic species of Fusarium in river water flowing to the sea could indicate long-distance dispersal in natural water environments.

[Multidrug-resistant tuberculosis in AIDS patients at the beginning of the millennium]

AIDS-related multidrug-resistant tuberculosis (MDRTB) emerged during the 90s in several countries around the world. In Argentina, the most notorious outbreak was documented in the Hospital Muñiz, which is still undergoing its aftermaths. In order to evaluate the situation in this hospital regarding MDRTB, we analysed clinical, demographic and epidemiological traits of the 53 male MDRTB-aids patients admitted during 2001-2003 at a ward especially dedicated to their isolation. Patients' mean age was 32 years, 70% lived in Buenos Aires suburbs. A history of illicit drug users or imprisonment was recorded in 68% and 26% of the patients, respectively. Severe immunodepression (CD4+ count < 100/microl) was found in 88% of the patients and 58% died. Mortality was associated with non-adherence to treatment and co-morbidity, but not with the genotype of the "M" strain, responsible for the original outbreak. Of 40 cases available for restriction fragment length polymorphism (RFLP), 29 (72.5%) resulted in cluster. RFLP patterns of 24 matched the "M" genotype. In this study, resistance to 5 or 6 drugs was found to be an indicator of disease due to the "M" strain. The "M" genotype associated significantly to previous admission at the Hospital Muñiz or imprisonment. In brief, 14 years after the detection of the first MDRTB-aids case, we report here the persistence and predominance of the original outbreak strain at the hospital. Stronger TB infection control measures are urgently needed in hospitals and jails in order to strengthen the declining trend of the MDRTB observed in our country towards the end of the last decade.

Multidrug-resistant tuberculosis outbreak among transvestite sex workers, Buenos Aires, Argentina

We describe the first outbreak of multidrug-resistant tuberculosis (MDR-TB) that occurred in Argentina among transvestite sex workers, and actions undertaken for its control. In Buenos Aires city, transmission was documented between 2001 and 2004 by conventional and molecular methods in a hotel where transvestites used to reside and work. The source case was traced back to 1998. Six secondary cases were diagnosed and treated. Thirty-two contacts were investigated. The outbreak strain had formerly caused nosocomial transmission in Rosario, a city 300 km from Buenos Aires. Our findings highlight the difficulties controlling MDR-TB in Argentina.

Multidrug-resistant tuberculosis in bone marrow transplant recipient

Multidrug-resistant tuberculosis (TB) is an increasing problem worldwide, however only three cases have been previously described in transplant recipients, especially involving lung and heart transplant. We describe a case of multidrug-resistant TB in an allogenic bone marrow transplant recipient with good response to second-line therapy.

Multidrug-resistant tuberculosis in HIV-negative patients, Buenos Aires, Argentina

Initial multidrug-resistant (MDR) tuberculosis (TB) in HIV-negative patients treated at a Buenos Aires referral hospital from 1991 to 2000 was examined by using molecular clustering of available isolates. Of 291 HIV-negative MDRTB patients, 79 were initially MDR. We observed an ascending trend of initial MDRTB during this decade (p=0.0033). The M strain, which was responsible for an institutional AIDS-associated outbreak that peaked in 1995 to 1997, caused 24 of the 49 initial MDRTB cases available for restriction fragment length polymorphism. Of those, 21 were diagnosed in 1997 or later. Hospital exposure increased the risk of acquiring M strain-associated MDRTB by approximately two and a half times. The emergence of initial MDRTB among HIV-negative patients after 1997 was apparently a sequel of the AIDS-related outbreak. Because the prevalence of M strain-associated disease in the study population did not level out by the end of the decade, further expansion of this disease is possible.

[Infectiousness and virulence of multidrug-resistant and drug susceptible tuberculosis in adult contacts]

Patients carrying multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have been considered traditionally as presenting a diminished epidemiological risk according to animal experimentation results. The experience obtained from the MDRTB/AIDS related epidemics showed MDRTB transmission to immunocompetent health care workers and adults close contacts. In this retrospective study, the infectiousness (measured as the frequency of intradermal test with PPD 2TU over 10 mm) and virulence (cases bacteriologically confirmed) among close contacts of patients with MDR and susceptible TB were evaluated. A total of 97 contacts of 37 MDRTB patients vs. 356 contacts of 100 patients with susceptible TB were studied. No statistical differences were found in PPD 2 UT positivity and TB cases between both contact groups, nor in relation to HIV seropositivity of index cases. According to these observations, MDR strains of M. tuberculosis present similar infectiousness and virulence compared with susceptible strains.

[Multidrug-resistant tuberculosis associated with AIDS (kinetics of nosocomial epidemics of multidrug-resistant tuberculosis associated with AIDS. Possible transformation into endemic disease]

The increase in the incidence of AIDS-related tuberculosis over the last decades has fueled the dissemination of multiple drug resistance tuberculosis (including resistant strains to INH and rifampin). This has now been recognized in a variety of settings including hospitals, prisons and shelters. We have identified a nosocomial epidemic at the Muñiz Hospital in the city of Buenos Aires, Argentina. This has evolved as one of the largest institutional outbreaks yet to be recognized. The purpose of this paper is to characterize the evolution of this outbreak which at the end of 1997 had involved in excess of 500 cases. Among the 3,322 patients discharged at the Muñiz Hospital during the years 1996-1997 with the diagnosis of tuberculosis, 440 (13.24%) were discharged with the diagnosis of multiple drug resistance tuberculosis. The immediate mortality (during the ensuing four months following the bacteriological diagnosis) was of 91.3% of cases in 1995 and decreased progressively to 65.9% in 1996 and 55.9% in 1997. The bacteriological confirmation of the diagnosis was made after the patients death in a decreasing number of cases, going from 72.5% of the cases in 1995 to 28.3% of the cases in 1997. Despite the significant progress achieved with regard to the diagnosis and treatment of multiple drug resistance tuberculosis, the measures undertaken to decrease the spread of the cases have had limited success. This is chiefly attributable to the inability to isolate cases. This has continued to promote nosocomial spread of multiple drug resistance tuberculosis in our environment.

Phase II trial of recombinant interferon-alpha2b in patients with advanced intractable multidrug-resistant pulmonary tuberculosis: long-term follow-up

SETTING

Multidrug-resistant tuberculosis patients without human immunodeficiency virus (HIV) infection, with Mycobacterium tuberculosis resistant to almost all of the available drugs.

OBJECTIVE

Limited phase II trial with recombinant interferon-alpha2b in five chronic multidrug-resistant tuberculosis patients.

METHODS

Three million units of r-IFN-alpha2b were administered subcutaneously every week for 12 weeks. Before and after treatment, and during a 30-month follow-up period, the patients underwent clinical and radiological examination, together with bacteriological, immunological and routine laboratory testing.

RESULTS

Two of the five patients became long-term sputum smear and culture negative after r-IFN-alpha2b therapy; one of the patients showed clinical improvement and negative smear after therapy, but remained culture positive. The other two patients showed no response.

CONCLUSION

The results of this trial suggest that r-IFN-alpha2b should be evaluated further in multidrug-resistant tuberculosis in prospective controlled trials.