Use of microscopic morphology in smears prepared from radiometric cultures for presumptive identification ofMycobacterium tuberculosis complex,Mycobacterium avium complex,Mycobacterium kansasii, andMycobacterium xenopi

Mycobacterium tuberculosis often exhibits serpentine cording when grown in liquid medium, whereas Mycobacterium kansasii can be larger and cross-barred. We assessed the use of these morphologic characteristics as a cost-effective method for rapid presumptive identification of isolates from BACTEC bottles. Without specific training, using the Kinyoun acid-fast stain, definitive cording was found in 237 of 373 specimens positive forM. tuberculosis (64%) and cross-barring was recognized within 63 of 76 (83%) of the specimens positive for M. kansasii, giving sensitivities specificities, positive predictive values, and negative predictive values of 63.5, 96, 92, and 79%, respectively, for M. tuberculosis and 83, 95, 59, and 98%, respectively, for M. kansasii. With training and experience, these results improved to 74.5, 98, 96, and 84% and 93, 98, 79, and 98%, respectively. The major improvements were in distinguishing the pseudocording, or loose aggregation ofMycobacterium avium complex from M. tuberculosis and the long beaded forms of Mycobacterium gordonae from M. kansasii. Mycobacterium asiaticum and Mycobacterium szulgai, which rarely occur, are genetically related to M. kansasiiand morphologically difficult to distinguish. In defined circumstances, serpentine cording and cross-barring can be used for rapid presumptive identification of M. tuberculosisand M. kansasii, respectively, and as guides for initial probe selection to reduce costs.

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OP0081 A CASE OF ATYPICAL MYCOBACTERIUM INFECTION COMPLICATING EXTRA-NODAL ROSAI-DORFMAN DISEASE IN A PATIENT WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.2415 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 43.3-44

Author(s):

K. Su ◽

G. Hagan ◽

S. Tosounidou ◽

C. Gordon ◽

J. Reynolds

Keyword(s):

Weight Loss ◽

Case Report ◽

Mycobacterium Avium ◽

Salmonella Enterica ◽

Mycobacterium Avium Complex ◽

Clinical State ◽

Low Grade ◽

Mycobacterium Kansasii ◽

Mycobacterium Infection ◽

Rosai Dorfman Disease

Background:We present the case of a 28 year old Black-British female with severe SLE requiring treatment with rituximab in 2012 due to persistent low-grade activity and severe episodes of pleuro-pericardial effusions, pancytopaenia, fever and weight lossHer other background includes beta-thalassaemia trait and excision of calcific fibrotic tissue on bilateral anterolateral orbits in 2015.In 2018 she reported an 18-month history of non-tender, non-fluctuant, slow growing left thigh mass with USS revealing a well demarcated subcutaneous complex cystic lesion of ~2x4x7cm. There was no preceding trauma or skin infection. Histology from a needle biopsy revealed diffuse histiocytosis with positive immunohistochemistry (ICH) for S100, CD68 and CD31, it was negative for CD1a, consistent with Extra-nodal Rosai-Dorfman disease (RDD).She developed constitutional symptoms after reporting months of gradual weight loss with gradual ESR, CRP rise and leucocytosis. Her SLE symptoms were stable and given lack of SLE-specific symptoms; PET-CT was used to identify systemic RDD; the thigh mass showed strong FDG avidity along with a small focus of uptake in the small bowel, thought to be RDD related with no other areas of uptake.She had ongoing ooze from the enlarging thigh lesion (5 x 26 x 15 cm), this was sent for MCS and AAFB; which isolated Mycobacterium avium. She was treated with rifampicin, ethambutol and clarithromycin resulting in improved thigh lesion, constitutional symptoms and inflammatory markers.Objectives:[1]To describe a rare associated complication of severe SLE and to educate and inform clinicians regarding possible masquerades of disease[2]To education and inform about the approach to diagnosis of mycobacterium infection.Methods:Case report and literature review.Results:Mycobacterium infections rarely complicate RDD; to date, only one case report is published involving an HIV infected patient with RDD confirmed on LN biopsy presenting with splenomegaly and treated with oral corticosteroids (OCS) complicated by Mycobacterium avium complex and Salmonella enterica confirmed on bone marrow biopsy/culture, similar to our patient, he presented with constitutional symptoms and weight loss(2).Mycobacterium can also mimic RDD, a case report has described a 74 year old with tender lymphadenopathy diagnosed with RDD on LN biopsy. She was treated with IV and OCS, but was unresponsive. A repeat LN biopsy and CT imaging revealed the presence of mycobacterium kansasii; her biopsy was positive for CD68/S100 throughout. Of note, she had high levels of anti-interferon autoantibodies and was diagnosed with adult-onset immunodeficiency syndrome(3).Conclusion:This case illustrates the need for a MDT approach for multi-system diseases such as SLE and RDD, and the need to consider atypical infections when blood tests are incongruent with clinical state.References:[1]Bruce-Brand C, Schneider JW, Schubert P. Rosai-Dorfman disease: an overview. J Clin Pathol. 2020 Nov;73(11):697-705. doi: 10.1136/jclinpath-2020-206733.[2]Olmedo-Reneaum A, Molina-Jaimes A, Conde-Vazquez E, Montero-Vazquez S. Rosai-Dorfman disease and superinfection due to Salmonella enterica and Mycobacterium avium complex in a patient living with HIV. IDCases. 2020 Jan 14;19:e00698.[3]King YA, Hu CH, Lee YJ, Lin CF, Liu D, Wang KH. Disseminated cutaneous Mycobacterium kansasii infection presenting with Rosai-Dorfman disease-like histological features in a patient carrying anti-interferon-γ autoantibodies. J Dermatol. 2017 Dec;44(12):1396-1400.Image 1.Table 1.SLE Clinical HistoryDiagnosed 2006 (‘97 ACR Classification Criteria)Clinical -Polyarthritis -Glandular (lacrimal swelling) -Pericardial effusion/Pleural Effusion -MyositisSerological -Anti-nuclear antibody (ANA) -Anti-dsDNA -Anti-U1-RNP -Anti- SS-A/Ro -Lupus AnticoagulantPrevious SLE Treatment -Hydroxychloroquine (HCQ) -Methotrexate (MTX) -Azathioprine (AZA) -Rituximab (RTX)Disclosure of Interests:None declared

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