Mycobacterium kyorinense infection

Pleuritis Caused by Mycobacterium kyorinense without Pulmonary Involvement

We herein describe the first known case of pleuritis caused by Mycobacterium kyorinense without pulmonary involvement. A 48-year-old man undergoing immunosuppressant therapy presented with cough and dyspnea. An accumulation of pleural fluid was noted; however, computed tomography revealed no pulmonary lesions. Cultures of the fluid yielded non-tuberculous mycobacteria, which was identified as Mycobacterium kyorinense. The patient recovered after 6 months of therapy with clarithromycin and moxifloxacin. Clinicians should be aware that Mycobacterium kyorinense can cause pleuritis without pulmonary involvement. When mycobacterial species are isolated from the pleural fluid, precise identification and drug susceptibility testing are warranted.

Emergence of Rare Species of Nontuberculous Mycobacteria as Potential Pathogens in Saudi Arabian Clinical Setting

Background

Clinical relevance of nontuberculous mycobacteria (NTM) is increasing worldwide including in Saudi Arabia. A high species diversity of NTM’s has been noticed in a recent study. However, the identification in diagnostic laboratories is mostly limited to common species. The impact of NTM species diversity on clinical outcome is so far neglected in most of the clinical settings.

Methodology/Principal Findings

During April 2014 to September 2015, a nationwide collection of suspected NTM clinical isolates with clinical and demographical data were carried out. Primary identification was performed by commercial line probe assays. Isolates identified up to Mycobacterium species level by line probe assays only were included and subjected to sequencing of 16S rRNA, rpoB, hsp65 and 16S-23S ITS region genes. The sequence data were subjected to BLAST analysis in GenBank and Ez-Taxon databases. Male Saudi nationals were dominated in the study population and falling majorly into the 46–59 years age group. Pulmonary cases were 59.3% with a surprising clinical relevance of 75% based on American Thoracic Society guidelines. Among the 40.7% extra-pulmonary cases, 50% of them were skin infections. The identification revealed 16 species and all of them are reporting for the first time in Saudi Arabia. The major species obtained were Mycobacterium monascence (18.5%), M. cosmeticum (11.1%), M. kubicae (11.1%), M. duvalli (7.4%), M.terrae (7.4%) and M. triplex (7.4%). This is the first report on clinical relevance of M. kubicae, M. tusciae, M.yongonense, M. arupense and M.iranicum causing pulmonary disease and M. monascence, M. duvalli, M. perigrinum, M. insubricum, M. holsaticum and M. kyorinense causing various extra-pulmonary diseases in Saudi Arabia. Ascites caused by M. monascence and cecum infection by M. holsaticum were the rarest incidents.

Conclusions/Significance

To the first time in the country, clinical significance of various rare NTM’s are well explored and the finding warrants a new threat to the Saudi Arabian clinical settings.

Nontuberculous mycobacteria (NTM) are ubiquitous in nature and they are opportunistic pathogens. In the last decade, infections caused by NTM’s increased—around the world in immune-suppressed and immune-competent individuals and Saudi Arabia is not an exception. Developments in diagnostic technologies increased the identification of several new or rare species of NTM’s. Indeed, the species diversity of NTM has a direct impact on clinical outcome and therapies. Saudi Arabian clinics so far report only the common species of NTM’s and rare species are mostly neglected due to the lack of proper infrastructure or ignorance. To the first time in the country, an exploration on the existence of clinically relevant rare NTM species was conducted on a nationwide level. The findings showed a huge diversity of rare NTM species causing both pulmonary and extra-pulmonary diseases. Clinical relevance of pulmonary infection based on American Thoracic Society guidelines was confirmed as an aggressive 75%, which is really alarming. Interestingly, 16 species of NTM’s were isolated in the study, and all of them are reporting for the first time in country. Overall finding shows Saudi Arabia faces serious threat from rare NTM species with high clinical significance and warrants the immediate need for more advanced infrastructure.

Microbiological features and clinical relevance of new species of the genus Mycobacterium

Nontuberculous mycobacteria (NTM) are present in the environment, mainly in water, and are occasionally responsible for opportunistic infections in humans. Despite the fact that NTM are characterized by a moderate pathogenicity, the diseases caused by NTM at various body sites are increasing on a worldwide level. Among over 150 officially recognized NTM species, only two or three dozen are familiar to clinicians, and even to most microbiologists. In this paper, approximately 50 new species described in the last 8 years are reviewed, and their role in human infections is assessed on the basis of reported clinical cases. The small number of reports concerning most of the "new" mycobacterial species is responsible for the widespread conviction that they are very rare. Their role is actually largely underestimated, mainly because they often remain unrecognized and misidentified. Aiming to minimize such bias, emphasis has been placed on more common identification pitfalls. Together with new NTM, new members of the Mycobacterium tuberculosis complex described in the last few years are also an object of the present review.

Pulmonary cavitary Mycobacterium kyorinense (M. kyorinense) infection in an Australian woman

We describe a patient with pulmonary cavitary pneumonia from whom we serially isolated Mycobacterium kyorinense, an organism not previously reported in Australia, or associated with cavitary disease. We discuss the clinical presentation, the isolation of the organism on several specimens and initial management. M. kyorinense is a recently characterized species, which has previously only been described in Japan and Brazil [1].

Whole-Genome Sequence of Mycobacterium kyorinense

We report here the first draft genome sequence of Mycobacterium kyorinense, which was described in 2009 and exhibits significant pathogenicity to humans.