“ Mycobacterium canettii ” Isolated from a Human Immunodeficiency Virus-Positive Patient: First Case Recognized in the United States

Abstract

We report the first case of tuberculosis caused by "Mycobacterium canettii" recognized in the United States. The pathogen was isolated from the cerebrospinal fluid of a 30-year-old Sudanese refugee. CASE REPORTA 30-year-old female Sudanese refugee was admitted to a Baltimore, MD, hospital in January 2005 with advanced AIDS complicated by prior episodes of pneumonia and a reported history of treated tuberculosis. Two months earlier, the patient had been admitted to a Kampala, Uganda, hospital for treatment of severe wasting (weight upon admission was 35 kg). There she demonstrated a stiff neck, but no cells or microorganisms were detected in the cerebrospinal fluid (CSF), and "she recovered very quickly on fluids, food, and fluconazole." Three sputa were smear negative for acid-fast bacilli (AFB), and a chest radiograph was normal.Upon admission to the Sinai Hospital of Baltimore, the patient complained of anorexia, nausea and vomiting, weight loss, right upper quadrant abdominal pain, inability to ambulate, and left foot pain. She was under an antiretroviral therapy that included stavudine, lamivudine, nevirapine, and sulfamethoxazole-trimethoprim for opportunistic infections. Her vital signs were normal but she appeared cachectic, with reduced muscle mass and strength, and had multiple hyperpigmented patches over both lower extremities, including a purplish discoloration on the plantar aspect of the left foot. Genital ulcers were present. The remainder of the examination was unremarkable.Initial diagnostic studies revealed neutropenia with a white blood cell (WBC) count of 1,100 cells/mm 3 (64% polymorphonuclear cells, 16% lymphocytes, and 16% monocytes), profound cellular immunodeficiency with a CD4 count of 2 cells/ mm 3 , and a human immunodeficiency virus viral load of 2,040 copies/ml. Bacterial cultures of blood, urine, and sputum were negative for pathogens, and a chest radiograph was unremarkable. A punch biopsy of the purplish lesion of the left foot revealed Kaposi's sarcoma, and a helical computer-assisted tomography (CAT) scan of the abdomen and pelvis demonstrated scattered, hypodense lesions of both the liver and spleen thought to possibly represent either parenchymal Kaposi's sarcoma, disseminated fungal or mycobacterial process, or a pyogenic infection. A CAT scan of her head showed mild right cerebellar atrophy. Three blood cultures (Bactec 13A medium) were negative for mycobacteria, and a bone marrow biopsy revealed no granuloma and no organisms by Kinyoun's AFB staining, methenamine silver, or periodic acid-Schiff stains. Growth detection for mycobacteria of the bone marrow specimen was also negative in the Bactec 13A medium. The patient was treated with ampicillin-sulbactam for possible hepatic microabscesses, acyclovir for genital herpes, and sulfamethoxazole-trimethoprim and weekly azithromycin for opportunistic infections. Anti-retroviral therapy was altered slightly to include abacavir, lamivudine, and nelfinavir. In spite of the applied treatment, the patient became progressively apathet...

The use of polymerase chain reaction for early diagnosis of tuberculosis in Mycobacterium tuberculosis culture

“…In coming years there should be changes in this conduct because of the challenges encountered by the frequent isolation, in humans, of new species of mycobacteria considered nonpathogenic or even mycobacteria of the TB complex, that show a different sensitivity profile to tuberculostatic agents and to tuberculinic tests. In this case, the use of techniques for isolation, species identification and determination of susceptibility profile is necessary (27,28).…”

Novel Multiplex Real-Time PCR Diagnostic Assay for Identification and Differentiation of Mycobacterium tuberculosis, Mycobacterium canettii, and Mycobacterium tuberculosis Complex Strains

“…Recently, a study by Pinsky and Banaei (31), which describes a real-time PCR for differentiation of the MTC, fails to differentiate M. tuberculosis and M. canettii and is also unable to differentiate between M. africanum, M. microti, M. pinnipedii, and M. caprae. A capability to identify the specific MTC species causing infection is important for determining the appropriate therapeutic regimen for the patient (34).…”

“…Cases of human TB caused by M. canettii have now been reported in Europe and America (12). In addition, recent reports have suggested that the number of true cases of TB caused by M. canettii may in fact be underrepresented (15,34). Therefore, an ability to differentiate M. tuberculosis and M. canettii not only is important from a patient treatment perspective but also will provide important epidemiological information for clinicians.…”

“…While drug-resistant strains of M. tuberculosis are emerging, it is considered sensitive to antituberculosis drugs such as pyrazinamide (PZA), a first-line antibiotic that reduces patient treatment time from 9 months to 6 months (27,35). However, M. canettii, which has been reported to cause TB in humans, is intrinsically resistant to PZA; therefore, the ability to differentiate it from M. tuberculosis is important for indicating the therapeutic regimen necessary for patient treatment (34).…”

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based Single Nucleotide Polymorphism Genotyping Assay Using iPLEX Gold Technology for Identification of Mycobacterium tuberculosis Complex Species and Lineages

“…Moreover, two members, M. bovis, the causative agent of zoonotic bovine tuberculosis, and M. canettii, an unusual member responsible for rare tuberculosis cases almost always exposed to Africa, are naturally resistant to pyrazinamide, a first-line antituberculous drug (18,34). Therefore, the rapid and reliable identification of MTBC isolates to the species level is of prime importance for timely selection of appropriate patient antibiotic treatment and also for epidemiological and public health considerations (36). Furthermore, various studies have recently identified distinct phylogenetic groupings within the human-adapted members of the MTBC (i.e., M. tuberculosis and M. africanum species), all of which are congruent (2, 5, 10, 14-16, 19, 20, 32).…”