Prolonged fever due to Mycobacterium avium complex (MAC) disease in advanced HIV infection: a public health concern

From March 1997 to June 1998, infectious etiologies of prolonged fever was prospectively investigated in 104 advanced human immunodeficiency virus (HIV) infected patients admitted to Siriraj Hospital. The etiology could be identified in 91 cases (87.5%). Of these, blood cultures from 68 patients yielded mycobacteria and fungi. Mycobacterium avium complex was the most common blood isolate in 24 per cent of the patients; followed by Mycobacterium tuberculosis in 20.2 per cent, Cryptococcus neoformans in 5.8 per cent, Penicillium marneffei in 5.8 per cent. During the course of febrile illness, 79 of the 91 patients (86.8%) exhibited focal lesions. Weight loss, elevated serum alkaline phosphatase were often found to be significantly more associated with MAC bacteremia (P < 0.05). Pulmonary involvement significantly correlated more with M. tuberculosis bacteremia than MAC bacteremia (P < 0.05). No cause could be identified in 13 cases. Mycobacterium blood culture alone established the etiologies in 68 cases (65.4%). Of the 25 patients with disseminated MAC (DMAC) infection, nine patients died during hospitalization. Another three cases died within a few months of appropriate anti-MAC chemotherapy. We concluded that the risk of DMAC infection in advanced AIDS patients in Thailand is high when low CD4 lymphocyte count is established. The prolonged fever resulted from DMAC in advanced HIV infection is warrant to be public health concern. Mycobacterium blood culture is a most valuable tool contributing to the diagnosis of infectious agents in this condition. The guidelines of 1997 USPHS/IDSA should be followed to give chemoprophylaxis against DMAC disease in patients with advanced HIV infection and a CD4 count less than 50 cells/mm3.     

Osteomyelitis due to Mycobacterium haemophilum in a patient with AIDS

A case of osteomyelitis resulting from infection with Mycobacterium haemophilum in a patient with the Acquired Immunodeficiency Syndrome (AIDS) and Hodgkin's disease is described. The clinical features and response to therapy are examined and compared to previous reported cases. Mycobacterium haemophilum infection in immunocompromised patients usually results in cutaneous lesions but osteomyelitis may be the presenting feature. Tissue samples should be obtained early for microbiological examination and treatment should consist of surgical debridement and appropriate antimicrobial therapy.     

New trends in the drug therapy of localized and disseminated Mycobacterium avium complex infection

Recent advances in the drug therapy of localized and disseminated infection with Mycobacterium avium complex (MAC) are reviewed. MAC infection is the most commonly reported bacterial infection in patients with AIDS, and the frequency of this infection in patients negative for the human immunodeficiency virus (HIV) is increasing. The main portals of entry for MAC are the gastrointestinal and respiratory tracts. Localized MAC infection is more common in HIV-negative than HIV-infected patients. The symptoms of disseminated MAC disease are those typical of advanced HIV disease. The most reliable diagnosis is provided by blood cultures; radiometric culturing techniques are favored. The overall treatment of MAC infection has improved greatly with the introduction of new agents during the past 15 years; survival time has been extended. Clarithromycin and azithromycin have proven effective against both localized and disseminated MAC infection. Clarithromycin is the cornerstone of therapy for disseminated infection. Ciprofloxacin has been successfully used to treat disseminated infection as part of a four-drug regimen including rifampin, ethambutol, and clofazimine. Rifabutin has substantial efficacy when combined with other agents. Liposomal aminoglycosides, such as amikacin, and interferon gamma have shown some initial promise. Rifabutin is currently recommended for the prevention of MAC disease in HIV-infected patients. Clarithromycin and azithromycin have also shown efficacy for prophylaxis, and fluoroquinolones may play a preventive role as well. New drug therapies are improving the outlook for persons infected with MAC.     

Pathobiological significance of colony morphology in Mycobacterium avium complex

There have been considerable political and organizational moves to involve 'consumers' (patients, carers, service users, potential users, local communities and the public at large) in the provision, planning and monitoring of health services. Such developments beg the question 'what constitutes good practice in user involvement?'. Taking user views into account relates not only to obtaining feedback on 'hotel' aspects of care (issues such as food and cleanliness) but also to the potential for patient input to clinical audit and the standards by which care itself is measured. Recent policy statements specifically advocate involving users in the process and product of clinical audit. In practice, 'involvement' has meant anything from passing on information to full and active participation in partnership with professionals. This paper outlines some of the issues raised in the published literature on user involvement in clinical audit. Suggesting that real involvement refers to users as active participants, not passive recipients, the paper documents the increasing policy commitment to user involvement and considers issues that influence how the rhetoric is put into practice.     

Sequence-based differentiation of strains in the Mycobacterium avium complex

The complete 16S-23S rDNA internal transcribed spacer (ITS) was sequenced in 35 reference strains of the Mycobacterium avium complex. Twelve distinct ITS sequences were obtained, each of which defined a "sequevar"; a sequevar consists of the strain or strains which have a particular sequence. ITS sequences were identified which corresponded to M. avium (16 strains, four ITS sequevars) and Mycobacterium intracellulare (12 strains, one ITS sequevars). The other seven M. avium complex strains had ITS sequences which varied greatly from those of M. avium and M. intracellulare and from each other. The 16S-23S rDNA ITS was much more variable than 16S rDNA, which is widely used for genus and species identification. Phylogenetic trees based on the ITS were compatible with those based on 16S rDNA but were more detailed and had longer branches. The results of ITS sequencing were consistent with the results of hybridization with M. avium and M. intracellulare probes (Gen-Probe) for 30 of 31 strains tested. Serologic testing correlated poorly with ITS sequencing. Strains with the same sequence were different serovars, and those of the same serovar had different sequences. Sequencing of the 16S-23S rDNA ITS should be useful for species and strain differentiation for a wide variety of bacteria and should be applicable to studies of epidemiology, diagnosis, virulence, and taxonomy.     

Pulmonary Mycobacterium avium complex disease without dissemination in HIV-infected patients

Pulmonary disease due to Mycobacterium avium complex (MAC) without evidence of dissemination is uncommon in HIV-infected patients. Five cases were observed over a 2-year period. All patients had AIDS and the median CD4 cell count at the time of presentation was 90 x 10(6)/L. Radiographic patterns included unilobar alveolar infiltrates or diffuse alveolar densities. All patients had a favorable clinical response to antimycobacterial chemotherapy with a median follow-up period of 10 months. MAC should be considered in HIV-infected patients with positive respiratory samples for acid-fast bacilli and pulmonary infiltrates. Patients with such findings in whom presumptive therapy for tuberculosis has failed should receive broad-spectrum antimycobacterial chemotherapy until final identification is available.     

Polyclonal Mycobacterium avium complex infections in patients with nodular bronchiectasis

P2X purinoceptors have been suggested to participate in transduction of painful stimuli in nociceptive neurons. In the current experiments, ATP (1-10 mM), alpha,beta-methylene-ATP (10-30 microM) and capsaicin (10 nM-1 microM) were applied to neurons impaled with high resistance microelectrodes in rat dorsal root ganglia (L4 and L5) isolated in vitro together with the sciatic nerve and dorsal roots. The agonists were either bath applied or focally applied using a picospritzer. GABA (100 microM) and 40-80 mM K+ solutions gave brisk responses when applied by either technique. Only three of 22 neurons with slowly conducting axons (C cells) showed evidence of P2X-purinoceptor-mediated responses. Only two of 13 cells which responded to capsaicin (putative nociceptors), and none of 29 cells with rapidly conducting axons (A cells), responded to the purinergic agonists. When acutely dissociated dorsal root ganglion cells were studied using patch-clamp techniques, all but four of 30 cells of all sizes responded with an inward current to either ATP or alpha,beta-methylene-ATP (both 100 microM). Our data suggest that few sensory cell bodies in intact dorsal root ganglia express functional purinoceptors.     

Molluscum contagiosum-like papules within the scope of disseminated infection with Mycobacterium avium complex in an AIDS patient

A 38-year-old HIV-positive man had several attacks of high fever associated with extensive perspiration over a 10-week period. Simultaneously, he developed molluscum contagiosum-like papules and an erythematous plaque on the face, ulcerated papules on both shoulders and buttocks and subcutaneous nodules on the arms. Histological examination of biopsy specimens revealed a diffuse, histiocytic infiltrate with abundant rod-shaped bacteria. Mycobacterium avium complex was cultured from the tissue and Mycobacterium avium complex DNA was detected by the polymerase chain reaction. The diagnosis of disseminated disease was additionally confirmed by culturing Mycobacterium avium complex from blood, sputum and stool. The skin lesions healed completely within 10 weeks by a multiagent as the patient was treated with a drug therapy. We describe the differential diagnosis, diagnostic procedures and therapy of disseminated infection with Mycobacterium avium complex.     

Mycobacterium avium complex and Mycobacterium tuberculosis in patients infected with the human immunodeficiency virus

Primary care physicians play an important role in identifying and treating bacterial infections in adults infected with the human immunodeficiency virus (HIV). Mycobacterium avium complex and Mycobacterium tuberculosis are pathogens that can cause systemic or local infection in these patients. We review the epidemiology, pathogenesis, clinical presentation, and principles of treatment for these two mycobacterial pathogens. Because M tuberculosis disease is preventable and curable and yet communicable, physicians should maintain a high degree of suspicion for tuberculosis in HIV-infected adults. In comparison, the goal of treating M avium complex in patients with advanced HIV disease is to reduce constitutional symptoms and improve survival.