Clinical and radiological features of Mycobacterium kansasii infection and Mycobacterium simiae infection

Abstract

This retrospective study sought to systematically identify clinical and radiological features of Mycobacterium kansasii and Mycobacterium simiae infections. The sample included consecutive patients with a culture-positive diagnosis of M. simiae infection (n=102) or M. kansasii infection (n=62) derived from the databases of the Laboratory of Microbiology of a tertiary medical centre and two outpatient tuberculosis centres. Data on patient background and clinical features were collected, and chest radiographs were analysed. Sixty percent of the M. kansasii group were native born compared to 18% of the M. simiae group (p=0.0001). M. simiae infection was associated with a higher rate of co-morbid disease, including diabetes mellitus, heart disease, and malignancy. A similar rate of lung disease was found in both groups. Clinical symptoms were significantly more common in patients with M. kansasii infection. On radiological study, M. kansasii infection was associated with more cavitations, and M. simiae infection with more pulmonary infiltrates. Patients with M. simiae infection had a higher likelihood of middle and lower lobe disease whereas patients with M. kansasii infection had more upper lobe disease (p=0.001). Pleural effusions and lymphadenopathy were found only in the presence of M. simiae infection. We concluded that there are major differences in the epidemiologic features of M. kansasii and M. simiae infection which have important diagnostic and therapeutic implications.

Refractory Bacteremia and Osteomyelitis Resulting in Fatal Bacteremic Pneumonia with Multiorgan Failure Caused by Mycobacterium simiae in a Non-Human Immunodeficiency Virus-Infected Adult

“…The commonly reported symptoms are productive cough, dyspnea, malaise, fever, sweat, and body weight loss (9). The lack of respiratory symptoms and the negative findings of chest radiographs suggest that our patient may have had long-term M. simiae colonization, which subsequently developed into multilobar pneumonia.…”

“…Clinical M. simiae isolation is usually from respiratory specimens, and most of them are from patients with AIDS, cancer, or chronic obstructive pulmonary disease (1). The clinical relevance of M. simiae isolation from respiratory specimens either as a colonizer of the respiratory tract or as a true pathogen causing pneumonia ranged from 9% to 24% (9,11). In our patient, M. simiae was recovered from multiple respiratory secretion specimens during hospitalization.…”

<i>Mycobacterium simiae</i>: a Possible Emerging Pathogen in Iran

“…Recently, this organism has been widely reported from other areas, including the Middle East (6)(7)(8)(9). Transmission of M. simiae to humans and possible environmental sources of this organism remain unclear; however, the routes of entry are probably respiratory and digestive tracts (10).…”

Pulmonary disease caused by Mycobacterium simiae in Iran’s national referral center for tuberculosis

“…M. simiae infections have been found in various regions such as the southern United States, Israel, and Cuba [6][7][8][9][10]. The infections are most commonly found in immunosuppressed hosts such as HIV-positive individuals, the elderly, children, and those with a history of tuberculosis (TB) [6,[11][12][13]. Furthermore, those with other diagnosed diseases such as diabetes mellitus, cardiovascular disease, and malignancy are more prone to acquiring M. simiae infection [11].…”

“…simiae can cause infections in diverse organs, especially in the respiratory system, causing variable clinical manifestations. A recent study indicated that individuals of certain ethnic origins, particularly those from the Middle East region, seemed to be more prone to contracting the disease [11].Only a few cases of M. simiae infections have been documented, and there is only one established case report of M. simiae in Iran [14].…”