Effects of Corynebacterium bovis on Engraftment of Patient-derived Chronic-Myelomonocytic Leukemia Cells in NSGS Mice.

Modeling chronic myelomonocytic leukemia (CMML) in immunodeficient NSGS mice relies on unique human CMML specimens and consistent murine engraftment. Only anecdotal comments have thus far supported the notion that research data may be altered by Corynebacterium bovis, an opportunistic cutaneous pathogen of immunodeficient mice. C. bovis disseminated by asymptomatic and clinically affected mice with hyperkeratotic dermatitis, resulting in resilient facility contamination and infectious recurrence. Herein we report that, compared with C. bovis PCR-negative counterparts, C. bovis PCR-positive NSGS mice developed periocular and facial hyperkeratosis and alopecia and had reduced metrics indicative of ineffective human CMML engraftment, including less thrombocytopenia, less splenomegaly, fewer CMML infiltrates in histopathologic sections of murine organs, and fewer human CD45+ cells in samples from murine spleen, bone marrow, and peripheral blood that were analyzed by flow cytometry. All CMML model metrics of engraftment were significantly reduced in the C. bovis PCR-positive cohort compared with the - negative cohort. In addition, a survey of comprehensive cancer center practices revealed that most murine facilities do not routinely test for C. bovis or broadly decontaminate the facility or its equipment after a C. bovis outbreak, thus increasing the likelihood of recurrence of invalidated studies. Our findings document that CMML engraftment of NSGS mice is diminished-and the integrity of murine research data jeopardized-by C. bovis infection of immunodeficient mice. In addition, our results indicate that C. bovis should be excluded from and not tolerated in murine facilities housing immunodeficient strains.

Active Tuberculosis in Patients with Psoriasis Receiving Biologic Therapy: A Systematic Review.

BACKGROUND: Biologic therapies pose a risk for opportunistic infections, especially for reactivating latent tuberculosis infection (LTBI). OBJECTIVE: The aim was to describe the clinical features and mortality rate of active Mycobacterium tuberculosis (TB) in psoriasis patients receiving biologic therapies. METHODS: A systematic review of PubMed, Google Scholar, ScienceDirect, Cochrane Library, and ClinicalTrials.gov databases was performed. Studies describing active TB in patients with psoriasis receiving biologic therapy from inception to May 31, 2018 were included. Clinical data as well as mortality rates were recorded. RESULTS: Fifty-one studies were included, evaluating 78 patients with active TB: 11 prospective studies, 13 retrospective, and 27 case reports/series. Most patients (73%) with active TB were male, the mean age was 48 ± 13 years, and 85% were of European or Asian origin. Pre-treatment LTBI screening was negative for 63% of patients. Disease presented in 33% of patients within the first 3 months of treatment, and in 51% within the first 6 months. Most patients (72%) presented with extra-pulmonary TB, and 49% had disseminated disease. The mortality rate was 7%. LIMITATIONS: Limitations of this review are its small sample size and inclusion of case reports. CONCLUSIONS: Some patients develop active TB despite LTBI screening. Clinicians initiating biologic therapy in patients with psoriasis should be aware of the clinical features of active TB in this scenario.

Higher serum 25-hydroxyvitamin D concentrations are associated with active pulmonary tuberculosis in hospitalised HIV infected patients in a low income tropical setting: a cross sectional study.

BACKGROUND: The inherent risk of developing tuberculosis (TB) in HIV- infected individuals is further enhanced by hypovitaminosis D. Interventions that offset HIV-associated immune deterioration potentially arrest disease progression and incidence of opportunistic infections including TB. Despite conflicting reports on association between vitamin D deficiency (VDD) and risk of TB, vitamin D (VD) supplementation remains a promising intervention. METHODS: We conducted a comparative cross-sectional study on 145 HIV+/pulmonary TB+ (PTB) and 139 HIV+/PTB- hospitalised patients to investigate association of vitamin D status and risk of PTB. Stratified random sampling was used to select archived serum specimens from participants enrolled in a randomised controlled trial (RCT) conducted to investigate the impact of using a point-of-care urine lipoarabinomannan strip test for TB diagnosis. PTB status was confirmed using sputum smear microscopy, culture or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D [25(OH) D] concentrations were assayed by competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment. Effect of VD status on duration of hospital stay and patient outcomes on follow up at 8 weeks were also investigated. Median serum 25(OH) D concentrations were compared using Mann-Whitney test and covariates of serum VD status were assessed using logistic regression analysis. RESULTS: Overall VDD prevalence in the cohort was 40.9% (95% CI: 35.1-46.8). Median serum 25(OH)D concentrations were significantly higher in HIV+/PTB+ group (25.3 ng/ml, IQR:18.0-33.7) compared to the HIV+/PTB- group (20.4 ng/ml, IQR:14.6-26.9), p = 0.0003. Patients with serum 25(OH) D concentration ≥ 30 ng/ml were 1.9 times more likely to be PTB+ compared to those with serum 25(OH) D concentrations < 30 ng/ml (odds ratio (OR) 1.91; 95% CI 1.1-3.2). PTB-related death was associated with higher odds of having 25(OH) D levels≥30 ng/ml. Age, gender, CD4+ count, combination antiretroviral therapy (cART) status, efavirenz based cART regimen and length of hospital stay were not associated with vitamin D status. CONCLUSIONS: The finding of an association between higher serum 25(OH) D concentrations and active PTB and TB-related mortality among hospitalised HIV-infected patients in the present study is at variance with the commonly reported association of hypovitaminosis and susceptibility to TB. Our findings though, are in concordance with a small pool of reports from other settings.

Opportunistic infections in rheumatoid arthritis patients exposed to biologic therapy: results from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis.

Objectives: This analysis set out to estimate the risk of opportunistic infection (OI) among patients with RA by biologic class. Methods: The British Society for Rheumatology Biologics Register for Rheumatoid Arthritis is a prospective observational cohort study established to evaluate safety of biologic therapies. The population included adults commencing biologic therapy for RA. The primary outcome was any serious OI excluding tuberculosis (TB). Event rates were compared across biologic classes using Cox proportional hazards with adjustment for potential confounders identified a priori. Analysis of the incidence of TB was performed separately. Results: In total, 19 282 patients with 106 347 years of follow-up were studied; 142 non-TB OI were identified at a rate of 134 cases/100 000 patient years (pyrs). The overall incidence of OI was not significantly different between the different drug classes; however, the rate of Pneumocystis infection was significantly higher with rituximab than with anti-TNF therapy (adjusted hazard ratio = 3.2, 95% CI: 1.4, 7.5). The rate of TB fell dramatically over the study period (783 cases/100 000 pyrs in 2002 to 38 cases/100 000 pyrs in 2015). The incidence of TB was significantly lower among rituximab users than anti-TNF users, with 12 cases/100 000 pyrs compared with 65 cases/100 000 pyrs. Conclusions: The overall rate of OI was not significantly different between drug classes; however, a subtle difference in the pattern of OI was seen between the cohorts. Patient factors such as age, gender and comorbidity were the most important predictors of OI.

Treatment of severe alcoholic hepatitis: past, present and future.

Alcoholic hepatitis (AH) manifests as a clinical syndrome characterized by recent jaundice and liver function deterioration in an actively drinking patient. The principal cause of AH is alcoholic steatohepatitis (ASH) defined histologically by the coexistence of steatosis, hepatocyte ballooning and satellitosis. While nonsevere AH usually responds to alcohol abstinence, severe AH, identified by Maddrey scoring ≥ 32, has a bad prognosis and is traditionally treated by a 28-day course of prednisone therapy. A recent trial, which showed no improvement of long-term survival but significant reduced mortality after 28 days of corticoid therapy compared to placebo, opens a debate on its efficacy. N-acetyl-cysteine supplementation combined with steroid therapy is also able to reduce the 28-day mortality compared to steroid alone. While guidelines recommend high-calorie intake and protein supplementation in decompensated liver diseases, intensive enteral nutrition together with corticoid treatment does not reduce mortality compared to corticoid alone in a recent study with ASH patients. Stimulation of liver regeneration through interleukin-22, granulocyte colony-stimulating factor or farnesoid X receptor agonists, inhibition of apoptosis, early liver transplantation and modulation of gut microbiota through antibiotic or faecal transplantation approaches constitute new therapeutic perspectives that are investigated in current clinical trials. Inhibition of oxidative stress, modulation of gut fungal populations and stimulation of progenitor cell proliferation and pro-regenerative inflammatory pathways constitute prospects for future human trials. For long-term survival, strategies for persistent alcohol abstinence remain the key of success, opening another large research field.

Anaemia, iron deficiency and susceptibility to infection in children in sub-Saharan Africa, guideline dilemmas.

Globally, anaemia, iron deficiency and infections are responsible for a majority of the morbidity and mortality that occurs among children. As iron is essential for erythropoiesis and the human immune system, as well as a crucial element for many pathogens, these three conditions often interact. This article considers the question - have the studies conducted so far unravelled the potential complex interaction between these factors sufficiently enough to be able to develop universally applicable guidelines about iron treatment in children? It is possible, however, that the area is too complex and diverse, with many sub-populations, and that not universal, but tailor-made guidelines are needed based on some agreed principles.

Successful management of Mycobacterium haemophilum lower extremity cutaneous infection in a matched-unrelated donor stem cell transplant recipient.

Nontuberculous mycobacterial infections can often occur in individuals with adequate immune function. Such infections typically have cutaneous involvement and are caused by rapidly growing mycobacterium. Other nontuberculous mycobacteria species, like Mycobacterium haemophilum, almost always present as opportunistic infections occurring in severely immunocompromised hosts. Here, we present a complicated and protracted course of diagnosing M. haemophilum lower extremity cutaneous infection in a matched-unrelated donor stem cell transplant recipient.

Acute dilated cardiomyopathy in a patient with beriberi and cryoglobulinaemic vasculitis: an unusual potential complication of two rare disorders.

We report the case of a 45-year-old patient who presented with acute dilated cardiomyopathy. During admission the patient was consecutively diagnosed with cryoglobulinaemic vasculitis and beriberi. In both diseases, cardiac involvement may occur as dilated cardiomyopathy. Thiamin deficiency was the final cause for the severe cardiac manifestations (cardiac acute beriberi or Shoshin syndrome), which returned to normal after thiamin supplementation.

[Phaeomycotic cyst caused by Exophiala xenobiotica in a patient with rheumatoid arthritis and lung cancer].

In black fungal infections, Exophiala species are frequently encountered as causative agents of human mycosis, particularly in immunocompromised patients. Among them, Exophiala jenselmei was previously reported as the most common etiological agent. Advances in molecular taxonomy proved this taxon to be heterogeneous, and led to newly introduced or redefined species. Exophiala xenobiotica is one of the novel species differentiated from E. jenselmei on the basis of molecular phylogeny.Here, we report a case of pheomycotic cyst caused by E. xenobiotica, which was well controlled via drainage and local thermotherapy. A 70-year-old man developed a cystic nodular lesion on the dorsum of his right thumb over the previous 3 months. He had been treated with prednisolone and methotrexate for 4 years for rheumatoid arthritis. The patient also had lung cancer with vertebral bone metastasis. Direct microscopic examination of the greenish pus aspirated from the cyst revealed mycelial elements. Culture of the pus on blood and Sabouraud dextrose agar yielded numerous black colonies multiple times. Histopathological examination of a biopsy specimen showed subcutaneous abscess formation surrounded by granulomatous tissues. Faintly pigmented pseudohyphae were seen within the abscess. The presence of melanin in the fungal cells was determined by Fontana-Masson staining. Initial microscopic examination of the isolate revealed annellidic conidiogenous cells, suggestive of E. jenselmei. This strain was further identified as E. xenobiotica by sequence analysis of the internal transcribed spacer (ITS) region of ribosomal RNA, showing a 100% sequence homology with the strain type.Pheomycotic cysts should be considered on identifying a slowly developing chronic subcutaneous abscess in immunocompromised patients. Sequencing is recommended for accurate species identification of causative pathogens.

Sporopachydermia cereana fungaemia in refractory leukaemia presenting as breakthrough infection during micafungin therapy.

The Sporopachydermia cereana species lives in decaying stems of cactus and is exceptionally rare as a human pathogen. A 57-year-old man with therapy-refractory acute promyelocytic leukaemia developed severe neutropaenia. After about 3 weeks of micafungin used as prophylaxis, he developed high fever, multiple pulmonary nodular infiltrates and a painful leg lesion. Blood culture yielded a yeast which was not identified by the Vitek 2 system. On ITS1-5.8S-ITS2 gene sequencing, the isolate was identified as S. cereana. Antifungal sensitivity by the Etest showed that the minimum inhibitory concentration for fluconazole was 0.75 µg/mL, and for anidulafungin, it was >32 µg/mL. He responded to liposomal amphotericin B but later died of Escherichia coli septicaemia. There were no cactus plants in the vicinity, suggesting that S. cereana might have alternative habitats.

Vitamin D status and incidence of pulmonary tuberculosis, opportunistic infections, and wasting among HIV-infected Tanzanian adults initiating antiretroviral therapy.

BACKGROUND: Maintaining vitamin D sufficiency may decrease the incidence of pulmonary tuberculosis and other infectious diseases. We present the first prospective study of vitamin D among human immunodeficiency virus (HIV)-infected adults receiving antiretrovirals in sub-Saharan Africa. METHODS: Serum 25-hydroxyvitamin D (25(OH)D) level was assessed at antiretroviral therapy (ART) initiation for 1103 HIV-infected adults enrolled in a trial of multivitamins (not including vitamin D) in Tanzania. Participants were prospectively followed at monthly visits at which trained physicians performed a clinical examination and nurses took anthropometric measurements and assessed self-reported symptoms. Cox proportional hazards models estimated hazard ratios (HRs) of morbidity outcomes. RESULTS: After multivariate adjustment, vitamin D deficiency (defined as a concentration of <20 ng/mL) had a significantly greater association with incident pulmonary tuberculosis, compared with vitamin D sufficiency (HR, 2.89; 95% confidence interval [CI], 1.31-7.41; P = .027), but no association was found for vitamin D insufficiency (defined as a concentration of 20-30 ng/mL; P = .687). Deficiency was also significantly associated with incident oral thrush (HR, 1.96; 95% CI, 1.01-3.81; P = .046), wasting (HR, 3.10; 95% CI, 1.33-7.24; P = .009), and >10% weight loss (HR, 2.10; 95% CI, 1.13-3.91; P = .019). Wasting results were robust to exclusion of individuals experiencing pulmonary tuberculosis. Vitamin D status was not associated with incident malaria, pneumonia, or anemia. CONCLUSIONS: Vitamin D supplementation trials for adults receiving ART appear to be warranted.

Pulmonary mucormycosis.

Mucormycosis (formerly zygomycosis) is a life-threatening opportunistic mycosis that infects a broad range of hosts with qualitative or quantitative defects in innate immunity, including patients with severe neutropenia, recipients of corticosteroids or other immunosuppressive medications, poorly controlled diabetes mellitus, and those with iron overload states. Mucormycosis has recently emerged as breakthrough sinopulmonary infection in hematologic patients and recipients of transplantation being on antifungal prophylaxis with Aspergillus-active antifungals that lack activity against Mucorales. Unlike pulmonary aspergillosis, the prognosis and outcome of pulmonary mucormycosis have not improved significantly over the last decade, mainly because of difficulties in early diagnosis and the limited activity of current antifungal agents against Mucorales. Recent evidence suggests a critical role for iron metabolism and fungal-endothelial cell interactions in pathogenesis of mucormycosis, and holds promise for development of novel therapeutic strategies. Currently, prompt initiation of antifungal therapy with a lipid amphotericin B-based regimen, reversal of underlying host factors, and aggressive surgical approach offers the best chances for survival of patients infected with this devastating mycosis.

¿Cómo manejar al paciente con artritis reumatoide y serología virus de hepatitis B, hepatitis C, virus de la inmunodeficiencia humana? / How does one manage patients with rheumatoid arthritis and positive serology to hepatitis B, hepatitis C, human immunodeficiency virus?

Las infecciones virales crónicas en un paciente reumático constituyen un reto diagnóstico y terapéutico. Algunos de los fármacos antirreumáticos modificadores de la enfermedad (FAME) más utilizados en la artritis reumatoide, como el metotrexato y la leflunomida, presentan riesgo de hepatotoxicidad. Con la terapia biológica, que es hoy en día ampliamente utilizada en pacientes refractarios a estos y otros FAME, se han descrito casos de reactivación de hepatitis B, incluso fulminante, especialmente con los antagonistas del TNF y rituximab, por lo que su utilización ha de ser cuidadosamente valorada y, generalmente, administrada junto con tratamiento antiviral. Sin embargo, no se han descrito casos de reactivación de hepatitis C tras terapia inmunosupresora. En los pacientes con serología VIH la administración de tratamiento inmunosupresor conlleva un elevado riesgo de infecciones oportunistas, aunque la nueva terapia antiviral altamente activa permite utilizar algunos fármacos en casos seleccionados (AU)

Chronic viral infections in rheumatic patients are a diagnostic and therapeutic challenge. Some of the disease-modifying antirheumatic drugs (DMARD) commonly used in rheumatoid arthritis, such as methotrexate and leflunomide, are hepatotoxic. With biological therapy, which is now widely used in patients refractory to these and other DMARD, some cases of reactivation of hepatitis B, even fulminant cases, have been reported, especially when employing TNF antagonists and rituximab, so their use must be carefully assessed and usually accompanied by antiviral therapy. However, there have not been reports of reactivation of hepatitis C after immunosuppressive therapy. In patients with HIV infection, administration of immunosuppressive therapy carries a high risk of opportunistic infections, although the new highly active antiviral therapy allows the use of some drugs in selected cases (AU)

Guidelines for supportive care in multiple myeloma 2011.

Supportive care plays an increasingly important role in the modern management of multiple myeloma. While modern treatments have significantly prolonged overall and progression free survival through improved disease control, the vast majority of patients remain incurable, and live with the burden of the disease itself and the cumulative side effects of treatments. Maintenance of quality of life presents challenges at all stages of the disease from diagnosis through the multiple phases of active treatment to the end of life. Written on behalf of the British Committee for Standards in Haematology (BCSH) and the UK Myeloma Forum (UKMF), these evidence based guidelines summarize the current national consensus for supportive and symptomatic care in multiple myeloma in the following areas; pain management, peripheral neuropathy, skeletal complications, infection, anaemia, haemostasis and thrombosis, sedation, fatigue, nausea, vomiting, anorexia, constipation, diarrhoea, mucositis, bisphosphonate-induced osteonecrosis of the jaw, complementary therapies, holistic needs assessment and end of life care. Although most aspects of supportive care can be supervised by haematology teams primarily responsible for patients with multiple myeloma, multidisciplinary collaboration involving specialists in palliative medicine, pain management, radiotherapy and surgical specialities is essential, and guidance is provided for appropriate interdisciplinary referral. These guidelines should be read in conjunction with the BCSH/UKMF Guidelines for the Diagnosis and Management of Multiple Myeloma 2011.

Empirical treatment of influenza-associated pneumonia in primary care: a descriptive study of the antimicrobial susceptibility of lower respiratory tract bacteria (England, Wales and Northern Ireland, January 2007-March 2010).

OBJECTIVES: To determine the susceptibility of lower respiratory tract (LRT) isolates of Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae to antimicrobial agents recommended by UK guidelines for treatment of pneumonia associated with influenza-like illness. METHODS: Analysis of antimicrobial susceptibility data from sentinel microbiology laboratories in England, Wales and Northern Ireland was carried out. Subjects comprised patients who had an LRT specimen taken in a general practitioner surgery or hospital outpatient setting between January 2007 and March 2010. The main outcome measurements were antimicrobial susceptibility trends of LRT isolates over time, between patient age groups and in different geographical regions. RESULTS: Susceptibility to tetracyclines or co-amoxiclav was high. Of the 70,288 and 45,288 isolates with susceptibility results for tetracyclines or co-amoxiclav, 96% and 92%, respectively, were susceptible. Overall susceptibility to ciprofloxacin, ampicillin/amoxicillin and macrolides was lower than for tetracyclines or co-amoxiclav and varied markedly by organism. There were few clinically relevant variations in susceptibility to doxycycline or co-amoxiclav over time, geographically or between age groups. CONCLUSIONS: The data support the use of doxycycline or co-amoxiclav as appropriate empiric treatment for LRT infection caused by the pathogens investigated, for patients in primary care.

Bacterial infections in cynomolgus monkeys given small molecule immunomodulatory antagonists.

Opportunistic infections (OIs) during the course of non-clinical toxicity studies can serve as a clinical indicator of immunosuppression. In monkeys, severity may be magnified since the possibility for fecal-oral and cage-to-cage transmission of bacteria exists, reserve capacity is low, and clinical signs of infection are not easily detected until the infectious process is well underway. This review summarizes a case study presented at the HESI-ILSI ITC-Sponsored workshop on Naturally Occurring Infections in Non-human Primates and Immunotoxicity Implications. It gives an overview on the impact of bacterial infections in monkeys on the development and regulatory assessment of three closely-related representative small molecule immunomodulatory (anti-inflammatory) drug candidates all inhibiting the same drug target. The infections, which sometimes progressed to bacteremia and death, originally manifested in the skin, upper respiratory tract, gastrointestinal tract, and less frequently as soft tissue abscesses. Infections were sporadic and not observed in all studies despite coverage of equivalent or higher systemic exposures or longer durations of treatment. To address concerns regarding inconsistency in the presentation and type of findings and their potential relationship to infection, steps were taken to identify causative agents (via culture, microscopy), implement various intervention and treatment regimens (supportive care, antibiotics, drug holiday), demonstrate reversibility of clinical and immune effects, and study major immune components/mechanisms affected (cytokine/stress protein profiling, immune cell phenotyping, and humoral/innate immune cell function tests). Appropriate diagnosis and characterization of the infection was critical to discrimination of these findings as a secondary pharmacologic effect rather than a direct drug-related target organ effect, and also guided clinical protocol design and regulatory acceptance.

Torsades de pointes upon fluconazole administration in a patient with acute myeloblastic leukemia.

Prolonged QT syndrome often causes torsades de pointes (Tdp), a potentially lethal arrhythmia. A 55-year-old woman with M4Eo who was receiving consolidation chemotherapy had an episode of prolonged QT and Tdp following fluconazole (FCZ) administration. Intravenous supplementation of magnesium sulfate and multiple attempts at electrocardioversion led to recovery from the arrhythmia. FCZ appears to contribute to the development of QT prolongation, in particular with low concentrations of serum potassium or magnesium. Although mechanisms of Tdp development in patients with QT prolongation remain to be determined, it is possible that FCZ administration leads to manifestation of Tdp. Special cautions should be exercised upon the emergence of QT prolongation following FCZ administration.

Otitis externa aguda por Enterobacter cloacae

Enterobacter engloba a diferentes especies bacterianas que junto con Pseudomona son responsables de infecciones oportunistas, especialmente en enfermos hospitalizados. Presentamos 3 casos de otitis externa aguda debidos a Enterobacter cloacae que correspondían a 2 varones y 1 mujer, sin antecedentes personales de interés, atendidos en Urgencias de nuestro hospital. El Laboratorio de Microbiología al que remitimos las muestras óticas nos confirmó el aislamiento de este germen, poco frecuente como causa de otitis externa en la literatura y más aún en ausencia de inmunodepresión u hospitalización previa. La evolución de todos los pacientes fue satisfactoria tras el tratamiento. Realizamos una revisión de la literatura al respecto (AU)

The relationship between the in vitro drug susceptibility of opportunist mycobacteria and their in vivo response to treatment.

SETTING: It is generally accepted that qualitative drug susceptibility tests established and validated for Mycobacterium tuberculosis are not applicable to opportunist (non-tuberculous) mycobacteria. Previous studies have shown that in vitro antimicrobial susceptibilities for opportunist mycobacteria, performed by the method of modal resistance (MR), correlate poorly with clinical response. Minimum inhibitory concentration (MIC) determination may provide better correlation with predicted clinical response than the conventional MR results. OBJECTIVE: To determine the relationship between quantitative in vitro sensitivity results for opportunist mycobacteria and their in vivo response to treatment. DESIGN: MICs were performed radiometrically with the Bactec TB-460 system; 35 M. avium complex isolates, 29 isolates of M. malmoense and 16 isolates of M. xenopi were tested. RESULTS: Susceptibility results were analysed in comparison with therapeutic outcome by Fisher's exact probability test. Only one significant association was found; in vitro resistance to ethambutol correlated with treatment failure for M. malmoense infections (P = 0.027). There were no other significant correlations between in vitro results and treatment outcome. CONCLUSION: Prediction of treatment outcome from in vitro susceptibility tests continues to be a problem in infections with opportunist mycobacteria.