Mycobacterium paraffinicum causing symptomatic pulmonary infection

A rare case of lymphadenitis and pulmonary disease caused by Mycobacterium paraffinicum

With over 150 species, non-tuberculous mycobacteria are increasingly recognized to be important human pathogens that pose diagnostic and management challenges. We report a rare case of cervical lymphadenitis and pulmonary disease caused by Mycobacterium paraffinicum in a 64-year-old man who presented with three-month history of increasing right-sided painless neck lump. His medical history included rheumatoid arthritis, which was managed with leflunomide and methotrexate. Computed tomography scans of his neck and thorax revealed a right lower neck and supraclavicular fossa cystic mass with peripheral enhancement and bilateral multiple small pulmonary nodules. M. paraffinicum was cultured from a fine-needle aspiration of the mass. Two out of three sputa were acid-fast bacilli smear positive but cultures did not yield any viable organism. He developed spontaneous discharge of purulent material via a sinus, which drained over two months and recovered with a completely healed sinus without any further treatment.

A case of pulmonary infection due to Mycobacterium paraffinicum from the Amazon Region

M. paraffinicum, a slow-growing scotochromogenic mycobacterium that uses paraffinic hydrocarbons other than methane, i.e. inorganic carbon sources, was originally isolated from soil samples, but only in 2010 definitely achieved the species status. We have described here the first report of pulmonary disease due to M. paraffinicum in Amazon Region.

Molecular Identification of Nontuberculous Mycobacteria in Humans in Zimbabwe Using 16S Ribosequencing

Background:

Several nontuberculous mycobacteria (NTM) were previously isolated from diverse environments such as water, soil, sewage, food and animals. Some of these NTM are now known to be opportunistic pathogens of humans.

Objective:

The main purpose of the study was to identify NTM isolates stored at the National Microbiology Reference Laboratory (NMRL) and were previously isolated from humans during a national tuberculosis (TB) survey.

Methods:

Pure NTM cultures already isolated from human sputum samples during the national TB survey were retrieved from the NMRL and used for this study. DNA was extracted from the samples and 16S ribosomal RNA gene amplified by polymerase chain reaction. The amplicons were sequenced and bioinformatics tools were used to identify the NTM species.

Results:

Out of total of 963 NTM isolates stored at the NMRL, 81 were retrieved for speciation. Forty isolates (49.4%) were found to belong to Mycobacterium avium-intracellulare complex (MAC) species. The other 41 isolates (50.6%) were identified as M. lentiflavum (6.2%), M. terrae complex (4.9%), M. paraense (4.9%), M. kansasii (3.7%), M. moriokaense (3.7%), M. asiaticum (2.5%), M. novocastrense (2.5%), M. brasiliensis (2.5%), M. elephantis (2.5%), M. paraffinicum (1.2%), M. bohemicum (1.2%), M. manitobense (1.2%), M. intermedium (1.2%), M. tuberculosis complex (1.2%), M. parakoreense (1.2%), M. florentinum (1.2%), M. litorale (1.2%), M. fluoranthenivorans (1.2%), M. sherrisii (1.2%), M. fortuitum (1.2%) and M septicum (1.2%). Two isolates (2.5%) could not be identified, but were closely related to M. montefiorense and M. phlei respectively. Interestingly, the MAC species were the commonest NTM during the survey.

Conclusion:

The study emphasizes the importance of identifying species of NTM in Zimbabwe. Future studies need to ascertain their true diversity and clinical relevance.

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.