Authors: Christopher S. Delos Santos, Rowena Nacionales-Virrey , Myrna T. Mendoza, Concepcion F. Ang RMT, Marc Agnew M. Cajucom, Sangnae Cho
Background: Diagnosing nontuberculous mycobacterial (NTM) disease especially among people living with HIV (PLHIV) is a challenge as misdiagnosis or underdiagnosis can happen in TB-endemic countries like the Philippines. To the best of our knowledge, this is the first local study describing the clinical, radiologic and microbiologic profile of NTM infections among patients with HIV/AIDS.
Methods: This descriptive study was conducted in the University of the Philippines-Philippine General Hospital (UP-PGH) involving PLHIV with NTM growth in their mycobacterial cultures done from November 1, 2013 to January 31, 2016. Available cultures with NTM growth from the Central Laboratory and Medical Research Laboratory were retrieved and underwent speciation by REBA Myco-ID and drug susceptibility testing (DST). Medical charts of these PLHIV with speciated NTM were reviewed for demographic and clinical data including signs and symptoms, past medical and personal history, HIV treatment status, laboratory results, and imaging findings. The diagnosis of NTM disease among patients were classified into definite NTM disease (pulmonary, extrapulmonary and disseminated), possible NTM disease, and not NTM disease. Treatment and clinical outcomes were also reviewed thereafter.
Results and Conclusions: There were 330 specimens from PLHIV submitted for mycobacterial cultures from November 1, 2013 to end of January 2016 - with 315 to the Central Laboratory and 15 to the Medical Research Laboratory. We retrieved 50 cultures with known NTM growth from different specimens: 46 from sputum, 2 from stool, 1 from tissue and 1 from abscess. Using the REBA Myco-ID test kit, we identified the specific NTM species in 39 of the 50 cultures. The rest turned out to be MTB on speciation (6) or had test failures or remained unidentified (5). The most common NTM specie, regardless of clinical significance was Mycobacterium fortuitum (15) followed by M. avium (9) and then M. mucogenicum (5). DST was done in 35 NTM isolates. All isolates of Mycobacterium avium complex (M. avium + M. intracellulare) were susceptible to clarithromycin but resistant to ethambutol and isoniazid while M. fortuitum was 100% sensitive to both ciprofloxacin and amikacin. Medical charts of 33 out of the 39 patients with NTM were reviewed and were categorized into definite NTM disease in 9 cases (8 pulmonary NTM and 1 extrapulmonary NTM), possible NTM disease in 15 cases and not NTM disease in 9 cases. Fever (79%), chronic cough (79%), and weight loss (71%) were the 3 most common presenting symptoms among PLHIV with definite and possible NTM disease. Patients in the definite NTM disease group have significantly lower CD4 than the 2 other groups. The
most common abnormal chest x-ray findings were non-specific infiltrates followed by nodular densities. Nine patients were treated for NTM with most patients also managed for TB presumptively and empirically. There were 2 deaths in the definite NTM disease group, both with M. avium isolates.