Mycobacterium kansasii osteomyelitis - a masquerading disease

Mycobacterium kansasii Infection in a Farmed White-Tailed Deer (Odocoileus virginianus) in Florida, USA

A 7-year-old farmed white-tailed deer doe was transported to a Levy County, Florida property and began to decline in health, exhibiting weight loss and pelvic limb weakness. The doe prematurely delivered live twin fawns, both of which later died. The doe was treated with corticosteroids, antibiotics, gastric cytoprotectants, and B vitamins but showed no improvement. The doe was euthanized, and a post mortem examination was performed under the University of Florida's Cervidae Health Research Initiative. We collected lung tissue after the animal was euthanized and performed histological evaluation, using H&E and Ziehl-Neelsen (ZN) staining, and molecular evaluation, using conventional PCR, followed by Sanger sequencing. The microscopic observations of the H&E-stained lung showed multifocal granuloma, while the ZN-stained tissue revealed low numbers of beaded, magenta-staining rod bacteria inside the granuloma formation. Molecular analysis identified the presence of Mycobacterium kansasii. This isolation of a non-tuberculous Mycobacterium in a white-tailed deer emphasizes the importance of specific pathogen identification in cases of tuberculosis-like disease in farmed and free-ranging cervids. We report the first case of M. kansasii infection in a farmed white-tailed deer (Odocoileus virginianus) in Florida. Although M. kansasii cases are sporadic in white-tailed deer, it is important to maintain farm biosecurity and prevent farmed cervids from contacting wildlife to prevent disease transmission.

Multiple Bone Destruction Secondary to Mycobacterium kansasii Pulmonary Disease: A Case Report

Mycobacterium kansasii infections predominantly manifest in immunocompromised people and are primarily responsible for lung disease and systemic disseminated infection. Osteopathy is a rare consequence of M. kansasii infection. Here, we present imaging data from a 44-year-old immunocompetent Chinese woman diagnosed with multiple bone destruction, particularly of the spine, secondary to M. kansasii pulmonary disease, which is easily misdiagnosed. The patient underwent an emergency operation after experiencing unexpected incomplete paraplegia during hospitalization, indicating an aggravation of bone destruction. Preoperative sputum testing and next-generation sequencing of DNA and RNA of intraoperative samples confirmed the diagnosis of M. kansasii infection. Treatment with anti-tuberculosis therapy and the subsequent patient response supported our diagnosis. Given the rarity of osteopathy secondary to M. kansasii infection in immunocompetent individuals, our case offers some insight into this diagnosis.

Pathogenic Determinants of the Mycobacterium kansasii Complex: An Unsuspected Role for Distributive Conjugal Transfer

The Mycobacterium kansasii species comprises six subtypes that were recently classified into six closely related species; Mycobacterium kansasii (formerly M. kansasii subtype 1), Mycobacterium persicum (subtype 2), Mycobacterium pseudokansasii (subtype 3), Mycobacterium ostraviense (subtype 4), Mycobacterium innocens (subtype 5) and Mycobacterium attenuatum (subtype 6). Together with Mycobacterium gastri, they form the M. kansasii complex. M. kansasii is the most frequent and most pathogenic species of the complex. M. persicum is classically associated with diseases in immunosuppressed patients, and the other species are mostly colonizers, and are only very rarely reported in ill patients. Comparative genomics was used to assess the genetic determinants leading to the pathogenicity of members of the M. kansasii complex. The genomes of 51 isolates collected from patients with and without disease were sequenced and compared with 24 publicly available genomes. The pathogenicity of each isolate was determined based on the clinical records or public metadata. A comparative genomic analysis showed that all M. persicum, M. ostraviense, M innocens and M. gastri isolates lacked the ESX-1-associated EspACD locus that is thought to play a crucial role in the pathogenicity of M. tuberculosis and other non-tuberculous mycobacteria. Furthermore, M. kansasii was the only species exhibiting a 25-Kb-large genomic island encoding for 17 type-VII secretion system-associated proteins. Finally, a genome-wide association analysis revealed that two consecutive genes encoding a hemerythrin-like protein and a nitroreductase-like protein were significantly associated with pathogenicity. These two genes may be involved in the resistance to reactive oxygen and nitrogen species, a required mechanism for the intracellular survival of bacteria. Three non-pathogenic M. kansasii lacked these genes likely due to two distinct distributive conjugal transfers (DCTs) between M. attenuatum and M. kansasii, and one DCT between M. persicum and M. kansasii. To our knowledge, this is the first study linking DCT to reduced pathogenicity.

Diagnosis and management of sternoclavicular joint infections: a literature review

The sternoclavicular joint (SCJ) is anatomically and clinically significant considering its proximity to important neuro-vascular structures like the subclavian vessels and the phrenic nerve. Infections of this joint masquerade multiple disorders, delay diagnosis and spread to the bone and deep tissues. There is no standardized workup and treatment protocol for sternoclavicular joint infections (SCJI) as defined in literature. Here, we review the existing literature to understand the current knowledge of the diagnosis and treatment of SCJI. We searched English publications in PubMed and included clinical trials, case reports, case series, retrospective cohort studies, literature and systematic reviews after excluding non-infectious etiology of SCJ pathologies. There are many risk factors for SCJI, such as immunocompromised status, intravenous drug use, trauma and arthropathies. But a large percentage of patients with disease have none of these risk factors. SCJIs can present with fever, joint swelling, immobility, and rarely with vocal cord palsy or dysphagia. While Staphylococcus aureus causes over 50% of SCJI cases, other pathogens such as Pseudomonas and Mycobacterium are frequently seen. When diagnosed early, the infection can be medically managed with antibiotics or joint aspirations. Most cases of SCJI, however, are diagnosed after extensive spread to soft tissue and bones requiring en-bloc resection with or without a muscle flap. Complications of undertreatment can range from simple abscess formation to mediastinitis, even sepsis. SCJIs are rare but serious infections prompting early detection and interventions. Most cases of SCJI treated adequately show complete resolution in months while retaining maximum functionality. Key features of proper healing include aggressive physiotherapy to prevent adhesive shoulder capsulitis and decreased range of motion.