Granulomatous spondylodiscitis: A case series with focus on histopathological features.

Objective: To report a series of Granulomatous Spondylodiscitis (GS) with focus on the histopathological features of the different forms of GS.Design: Case series.Setting: Pathology department of Charles Nicolle's Hospital of TunisiaParticipants: This study included 57 patients diagnosed with GS. There were 44 (77.2%) female patients and 13 (22.8%) male patients (sex ratio = 0.28).Intervention: Not applicable.Outcome measures: Clinical, microbiological and histopathological features were assessed in this study.Results: Fifty-seven patients with GS were enrolled: 51 tuberculous spondylodiscitis (TS), 2 fungal spondylodiscitis (FS), 3 brucellar spondylodiscitis (BS) and 1 case of sarcoidosis. Granulomas with necrosis were seen in 38 (66.6%) cases: 36 TS and 2 FS, while granulomas without necrosis were observed in the remaining 19 cases: 15 TS, 3 BS and 1 sarcoidosis. In all cases of TS, granulomas were epithelioid type, associated with histiocytic type granulomas in 7 cases. Caseous necrosis was seen in 35 cases of TS and suppurative granuloma in one case. The 3 cases of BS exhibited non-necrotizing and histiocytic type granulomas. The 2 cases of FS showed histiocytic, epithelioid and necrotizing granulomas. Necrosis was mixed: suppurative and caseous in both cases of FS. Sarcoidosis was characterized with epithelioid type granulomas without necrosis.Conclusion: Granuloma with caseous necrosis is highly suggestive of TS but does not rule out FS. Certain fungi can exhibit this type of necrosis as do tuberculosis species. Suppurative inflammation, although rare in TS, does exist. Histiocytic type granuloma without necrosis is suggestive of brucellosis.

Evaluation of PCR pncA-restriction fragment length polymorphism and PCR amplification of genomic regions of difference for the identification of M. bovis strains in lymph nodes cultures.

BACKGROUND: A rapid accurate identification of Mycobacterium bovis is essential for surveillance purposes. OBJECTIVES: A PCR pncA-Restriction Fragment Length Polymorphism (RFLP) and a multiplex PCR based on the detection of 3 regions of difference (RD-PCR): RD9, RD4 and RD1 were evaluated for the identification of M. bovis in lymph nodes cultures, in Tunisia, during 2013-2015. METHODS: Eighty-two M. tuberculosis complex strains were identified using the biochemical tests, GenoType MTBC assay, PCR pncA-RFLP and RD-PCR. RESULTS: The PCR pncA-RFLP showed that 54 M. bovis strains, identified by GenoType MTBC, had a mutation at position 169 of pncA gene. Twenty-eight strains did not show any mutation at this position 27 M. tuberculosis isolates and one M. caprae. The PCR pncA-RFLP had a sensitivity of 100.0% (95%CI: 93.3 -100.0) and a specificity of 100.0% (95%CI: 87.9-100.0) for identifying M. bovis. The RD-PCR showed that all M. bovis strains had the RD9 and RD4 deleted but presented RD1. RD-PCR also presented high sensitivity and specificity in detecting M. bovis strains (100.0%). CONCLUSIONS: PCR pncA-RFLP and RD-PCR represent very accurate and rapid tools to identify M. bovis. They can be easily implemented in each laboratory due to their low cost and easy use.

Whole-Genome Sequencing of Drug-Resistant Mycobacterium tuberculosis Strains, Tunisia, 2012-2016.

To investigate transmission of drug-resistant strains of Mycobacterium tuberculosis in Tunisia, we performed whole-genome sequencing on 46 multidrug-resistant strains isolated during 2012-2016. Core-genome multilocus sequence typing grouped 30 strains (65.2%) into 3 clusters, indicating extensive recent transmission and Haarlem clone predominance. Whole-genome sequencing might help public health services undertake appropriate control actions.