Disseminated Mycobacterium Avium-intracellulare Complex Infection Research Articles

Disseminated Mycobacterium avium-Intracellulare Complex Infection Presenting With Disseminated Intravascular Coagulation in an AIDS Patient.

Disseminated Mycobacterium avium-intracellulare complex (MAC) infection is one of the relatively common opportunistic infections seen in severely immunocompromised AIDS patients. A constellation of clinical, laboratory, and pathological features involving multiple organ systems are often present in disseminated MAC infection but disseminated intravascular coagulation (DIC) has not been previously described in association with this condition. To our knowledge, this is the first reported case of DIC complicating disseminated MAC infection in an AIDS patient. In this article, we present the case of a 33-year-old AIDS patient with high viral load, CD4 lymphocyte count of 1/mm3, who presented with nonspecific symptoms, anemia, thrombocytopenia, and increased lactate dehydrogenase, alkaline phosphatase, and ferritin. She also had abnormal coagulation parameters and features compatible with chronic DIC. Bone marrow biopsy assisted in making the correct diagnosis. She also later grew MAC from blood and sputum cultures. There were no other factors identified after a complete workup to explain DIC in this patient. After commencement of appropriate MAC therapy, she initially had a good response with some improvement of her coagulation parameters. Few months later, however, probably attributable to poor medication compliance, her condition deteriorated with development of thromboembolism, full-fledged DIC, sepsis, and an eventual fatal outcome. This case illustrates the importance of including disseminated MAC in the differential diagnosis of DIC in an AIDS patient.

Unusual Presentation for Unusual Infection: Disseminated Mycobacterium Avium-Intracellulare complex (MAC) in Patient with Sickle Cell Anemia Mimicking Blood Transfusion Reaction

Nontuberculous mycobacteria (NTM) are ubiquitous free living soil and water– borne organisms that cause numerous clinical syndromes including lymphadenitis, skin, soft tissue and pulmonary infections, however disseminated infection is almost exclusively in patient with severe immunocompromise (i.e:HIV, Hematological malignancy, and bone marrow transplant).Mycobacterium avium complex (MAC) is hard to diagnose as it is considered slow grower NTM.We describe a case of disseminated Mycobacterium avium-intracellulare complex infection in teenager with sickle hemoglobinopathy with unique presentation mimicking pRBCs transfusion reaction.Patient presented on three different occasions with tachycardia, hypotension and fever within 2-24 hours following pRBCs pheresis, all three episodes were investigated and were negative for transfusion reactions.Patient had central venous catheter (CVC), frequent admissions for vaso-occlusive painful episode, on hydrocortisone for adrenal insufficiency and off Hydroxyurea for two months.Diagnosis of mycobacterium avium complex bacteremia was confirmed by two positive blood cultures, whole body CT scan showed liver nodules, spleen nodules and lung nodules. Pulmonary dissemination was confirmed by Biopsy and culture, Lymphocyte markers showed severe lymphopenia with absolute CD4 count of 64.Patient underwent treatment with three month of four antibiotics followed by 9 months of three antibiotics with removal of the central line, follow up scan showed decrease size and numbers of nodules, patient started tolerating pheresis within one month of the antibiotics initiation.NTM infection should be added to the list of pathogens in sickle cell patients with CVCs and fever and should be considered in frequent pRBC transfusion like reaction with negative workup.Routine blood culture can identify rapid growing NTM but specific mycobacterial blood culture is required in case of other NTM species (slow grower). As dissemination almost always occurs in those with impaired cellular immunity, HIV testing and lymphocyte markers should be performedRemoval of involved CVCs is essential for the treatment as well as appropriate antimicrobial medications. DisclosuresNo relevant conflicts of interest to declare.

Disseminated Mycobacterium avium intracellulare complex Infection in a Patient with Polymyositis and Review of Five Other Non-AIDS Cases

Disseminated mycobacterium avium intracellulare complex (MAC) infection is quite rare in non-AIDS patients. We report here a man with polymyositis, complicated with disseminated MAC infection. Five other non-AIDS cases suffered from disseminated MAC infection in our hospital from 1988 to 2003 were also analyzed. Constitutive symptoms and signs including fever, body weight loss, cough, local soft tissue pain, hepatosplenomegaly and lymphadenopathy were frequently observed. The involvement in lung, bone, pleura, and lymph nodes are rather common. The time to correct diagnosis is usually delayed and in mis-diagnosed as ordinary TB is common. When a patient had prolonged differential diagnosis of fever, productive cough, lymphadenopathy, bone involvement or hepatosplenomegaly, differential diagnosis of disseminated MAC infection should be included.

Disseminated mycobacterium avium-intracellulare complex (MAC) infection in the era of effective antiretroviral therapy: is prophylaxis still indicated?

Before highly active antiretroviral therapies (HAART) were available for the treatment of persons with HIV infection, disseminated Mycobacterium avium-intracellulare complex (MAC) infection was one of the most common opportunistic infections that affected people living with AIDS. Routine use of chemoprophylaxis with a macrolide has been advocated in guidelines for the treatment of HIV-infected individuals if they have a circulating CD4+ cell count of < or =50 cells/microL. In addition, lifelong prophylaxis for disease recurrence has been recommended for those with a history of disseminated MAC infection. The introduction of HAART has resulted in a remarkable decline in the incidence of opportunistic infections and death among persons living with AIDS. Considerable reconstitution of functional immune responses against opportunistic infections can be achieved with HAART. In the case of infection with MAC, there has been a substantial reduction in the incidence of disseminated infections in the HAART era, even in countries where the use of MAC prophylaxis was never widely accepted. Moreover, the clinical picture of MAC infections in patients treated with potent antiretroviral therapies has shifted from a disseminated disease with bacteraemia to a localised infection, presenting most often with lymphadenopathy and osteomyelitis. Data from several recently conducted randomised, double-blind, placebo-controlled trials led to the current practice of discontinuing primary and secondary prophylaxis against disseminated MAC infections at stable CD4+ cell counts >100 cells/microL. These recommendations are still conservative as primary or secondary disseminated MAC infections are only rarely seen in patients who respond to HAART, despite treatment initiation at very low CD4+ cell counts. Potential adverse effects of macrolide therapy and drug interactions with antiretrovirals also metabolised via the cytochrome P450 enzyme system must be critically weighed against the marginal benefit that MAC prophylaxis may provide in addition to treatment with HAART. These authors feel that, unless patients who initiate HAART at low CD4+ cell counts do not respond to HIV-treatment, routine MAC prophylaxis should not be recommended. Nevertheless, the patient population for whom MAC prophylaxis may still be indicated in the era of HAART needs to be identified in prospectively designed clinical trials.

Increase in CD3 + CD4 - T lymphocytes in patients with AIDS and disseminated Mycobacterium avium-intracellulare complex infection: a prospective study

In a retrospective study, an increase in double-negative (CD3 + CD4 - CD8 -) (DN) T lymphocytes has been shown to be an independent predictor of disseminated Mycobacterium avium complex (D.MAC) infection in patients with less than 100 CD4 + T cells per mm 3. To better characterize this cell expansion, a prospective study was designed. From July 1995 to April 1997, 206 HIV-infected patients with less than 100 CD4 + T cells per mm 3 were prospectively followed up and immunophenotyped. The median followup was 1.1 year (+/-0.5 year), and 14 new D.MAC infections were diagnosed among 84 first AIDS-defining events. In univariate and multivariate analyses, D.MAC infections were the only opportunistic infection with a significant increase in DN T-cell percentage (median = 6.6; range = 1.7 to 24.5, P = 0.004) compared with patients without any opportunistic infection. This alteration in T-lymphocyte count could constitute a predictor for D.MAC infection in clinical practice.

Increases in CD3+CD4-CDS- T Lymphocytes in AIDS Patients with Disseminated Mycobacterium avium-intracellulare Complex Infection

Human immunodeficiency virus type 1 (HIV-1)-infected persons frequently have increased numbers of T cells bearing the gamma delta T cell receptor for antigen (gamma delta TCR). HIV-1-seropositive patients with < 100 CD4+ cells/mm3 were selected and divided into 9 AIDS-defining illness groups. The percentages of CD4+, CD8+, or double-negative CD4-CD8- (DN) T cells (most of the latter expressing the gamma delta TCR) for 8 symptomatic groups were compared with those for a reference group of asymptomatic HIV-1-infected patients. DN T cells were increased only in patients with disseminated Mycobacterium avium-intracellulare complex (MAC) infection, toxoplasmosis, or Kaposi's sarcoma. Multivariate logistic regression analysis revealed that the percentage of DN T cells was a better predictor of MAC infection than was the percentage of CD4+T cells. The increased percentage of DN T cells might have important implications for the understanding of gamma delta T cell physiology and for the early diagnosis and management of MAC infections in AIDS patients.

Endoscopic appearance of Mycobacterium genavense: case report and review of the literature

Mycobacteria are a frequent cause of infection in patients with acquired immunodeficiency syndrome (AIDS). Mycobacterium tuberculosis, the most common mycobacterial pathogen, is seen at all levels of immunosuppression, but usually does not involve the gastrointestinal tract.1 The most common mycobacteria involving the gastrointestinal tract is Mycobacterium avium-intracellulare complex (MAC).1 The clinical syndrome of disseminated MAC infection is characterized by anorexia, weight loss, diarrhea, lymphadenopathy and, frequently, liver function abnormalities.

Pentoxifylline aggravates impairment in tumor necrosis factor-alpha secretion and increases mycobacterial load in macrophages from AIDS patients with disseminated Mycobacterium avium-intracellulare complex infection.

Pentoxifylline, which inhibits tumor necrosis factor-alpha (TNF alpha), decreases human immunodeficiency virus replication in peripheral blood mononuclear cells. However, TNF alpha is important in cellular defense against M. avium-intracellulare complex (MAC), a common infection in advanced AIDS. The effect of pentoxifylline on mycobacterial colony counts in macrophages with in vivo MAC infection was evaluated, and differences in lipopolysaccharide (LPS)-induced TNF release in infected and uninfected macrophages were determined. Macrophages with in vivo MAC infection released much less TNF alpha in response to LPS (P = .01). The response was partially restored after antimycobacterial therapy. Pentoxifylline, in a concentration that inhibited LPS-induced TNF alpha by 52.4%, increased MAC counts by 2.5- to 50.0-fold. Thus, macrophages from AIDS patients with disseminated MAC infection are deficient in their ability to release TNF alpha, and further inhibition by pentoxifylline may be detrimental.

Rifabutin. A review of its antimicrobial activity, pharmacokinetic properties and therapeutic efficacy.

Rifabutin is a derivative of rifamycin S with activity against mycobacteria including atypical organisms such as Mycobacterium avium and M. intracellulare, also referred to as Mycobacterium avium-intracellulare complex (MAC). To date, rifabutin is the only drug to have been studied in large prospective placebo-controlled trials that has been shown to significantly reduce the incidence of disseminated MAC infection when administered prophylactically as a single agent to patients with acquired immune deficiency syndrome (AIDS). Initial studies also indicate that rifabutin may be a useful component of multiple drug regimens for the treatment of MAC infection, although further studies combining rifabutin with other recently available antimycobacterial drugs are required to determine the most effective regimens. When rifabutin is combined with at least two other antimycobacterial drugs, the combination appears to be of similar efficacy to rifampicin (rifampin)-containing regimens in patients with newly diagnosed pulmonary tuberculosis. Since available therapy for MAC infection in patients with AIDS is still suboptimal, rifabutin, at present the only first-line agent for prophylaxis against disseminated MAC infection in patients with advanced human immunodeficiency virus (HIV) infection, has the potential to make a valuable contribution to the continuing attempts to preserve the quality of life of patients with AIDS.