A 50-year-old man was treated with trimethoprim-sulfamethoxazole (TMP-SMX) for acute arthritis of his right big toe. Within a few days, he developed dyspnoea, hypoxaemia and diffuse pulmonary infiltrates. Symptoms improved with discontinuation of the antibiotic but worsened again with its reintroduction. An open lung biopsy was performed. We describe the workup performed and the factors that pointed to a final diagnosis of TMP-SMX-related pulmonary toxicity in the form of acute fibrinous organising pneumonia.

INTRODUCTION: Nontuberculous Mycobacterium species (NTM) are a group of pulmonary pathogens with an alarming increase in global incidence. Their indolent nature along with their susceptibility towards antibiotic resistance makes them difficult to eradicate. Mycobacterium Xenopi is an NTM commonly found in Canada and Europe. Described as a lung specific pathogen, it usually leads to nodular and cavitary infiltrates. With rising NTM infections there are increasing reports of M. Xenopi isolated in patients with chronic lung disease in the United States. We present a rare case of disseminated M. Xenopi.

INTRODUCTION: Nontuberculous mycobacterium (NTM) associated pulmonary infections are a rising cause for concerns globally. There has been a surge of NTM reported cases in the United States over the past decade. The most common pulmonary infections from NTM isolated are due to Mycobacterium avium complex (MAC), Mycobacterium kansasii, and Mycobacterium abscessus. Mycobacterium fortuitum group species are a subset of rapid growing mycobacteria (RGM) NTM that are encountered as emerging opportunistic pathogens. The group compromises of M. fortuitum, Mycobacterium peregrinum, Mycobacterium senegalense, Mycobacterium alvei, Mycobacterium houstonense, Mycobacterium neworleansense, Mycobacterium boenickei, Mycobacterium septicum, and Mycobacterium porcinum. This subgroup is rarely isolated in pulmonary infections. We present a rare case of mycobacterium conceptionense, houstonense, and senegalense complicating care for a patient with chronic moderate persistent asthma. CASE PRESENTATION:A 25-year-old female with a history of moderate persistent asthma and allergic rhinitis who presented to the pulmonary clinic for reticulonodular opacities in the left lung on chest x-ray, shortness of breath, productive cough, and hemoptysis. She had a computed tomography (CT) chest revealing mucus plugging in the bilateral lower lobes with bronchiectasis and bilateral reticulonodular opacities. Acid-Fast Bacillus (AFB) cultures revealed mycobacterium conceptionense, houstonense, and senegalense. Treatment was started with levofloxacin, doxycycline, and azithromycin. Repeat CT chest 3 months after starting treatment revealed improvement in bilateral opacities and mucous plugging. Symptoms were improved with minimal sputum production and only occasional cough. Repeat AFB cultures in 3, 6, and 9 months were unremarkable.DISCUSSION: Mycobacterium conceptionense, houstonense, and senegalense are a group of RGMs that are rarely described to cause pulmonary disease. Although incidence of Mycobacterium conceptionense, houstonense, and senegalense is rare, the pathogenic bacteria are typically noted to cause surgical wound infections, catheter-related infections, and disseminated cutaneous infections. Treatment is currently based off case series and individual experience. Cultures are typically sterile following approximately 6 to 8 weeks. Treatment should be continued for at least 3 to 6 months.CONCLUSIONS: Further studies are warranted to delineate management, treatment given rise of these rare indolent pulmonary infections and their possible impact on patients with chronic asthma.

Metabolic equivalent (MET) is a universally used concept to represent energy cost of physical activities. Physical activities are described as multiples of the standard resting energy value (1 MET). The value equating 1 MET to a VO2 of 3.5 ml/ kg/min was derived from a single 70 kg, 40-year-old male subject's resting oxygen consumption (VO2). This decade long convention based on one healthy non obese male's energy expenditure has been widely used in individuals of all ages, sexes, phenotypes and disease states. We intend to investigate the adequacy of this convention in our patient population where we have access to both Oxygen consumption (VO2) and conventionally calculated MET values. We used VO2 measured in Cardiopulmonary exercise testing to compare with MET levels derived independently from a stationary bike. Availability of both conventional MET and real time VO2 gives us the opportunity of querying the conventional relationship between these variables and assessing for a predictable variability based on patient characteristics such as age, sex, weight, BMI and type of disease state. METHODS: A total of 272 patients were retrospectively studied. VO2 at rest, VO2 at maximum exercise, METs at maximum exercise were used to query the above-mentioned relationship. Patients were asked to exercise from rest to peak exercise on stationary bike. Comparison in values in varying demographic and comorbidities were recorded. RESULTS: A total of 272 people were reviewed. Mean Resting VO2 for all patients was noted to be 3.37 ml/kg/min. This is significantly different from conventionally assumed resting VO2 of 3.5 (95% CI 3.24-3.49, P 0.0379). Additionally, resting Vo2 was noted to be significantly different for patients aged 60 and over (3.3), Patients with BMI <25 (3.88), Patients with BMI >30 (3.12) and females (3.29). 169 patients were noted to reach maximal exercise based on RER >1.15 while 102 patients could not reach maximal exercise. Maximal Vo2 to maximal MET ratio for patients with maximal studies was noted to be 2.28 (95% CI 2.13-2.43) and for patients with sub-maximal studies was 2.81 (95% CI 2.38-3.24). Both these values were significantly different from conventionally accepted relationship of 3.5. CONCLUSIONS: The value of a Vo2 to MET ratio has a significant variation when adjusted to demographics and activity level. Using MET as a single criterion for energy expenditure among different age groups, demographics and exercise levels is fraught with risk of miscalculating actual amount of energy expenditure. CLINICAL IMPLICATIONS: There is a need for prediction models that consider patient characteristics for predicting energy expenditure more precisely.