Bacillus cereus isolated from a positive bone tissue culture in a patient with osteolysis and high-titer anti-interferon-γ autoantibodies: A case report

Disseminated Non-tuberculous Mycobacteriosis with a Skull Lesion Controlled by Resection after Exacerbation during Antimicrobial Chemotherapy in a Patient Positive for Anti-IFN-γ-neutralizing Autoantibodies

A 48-year-old man presented with a fever and back pain and was referred to our hospital with multiple bone destruction and abscess formation. A sputum examination revealed Mycobacterium intracellulare, and pathological findings revealed an indistinct granuloma and acid-fast bacilli, leading to a diagnosis of disseminated nontuberculous mycobacteriosis. Anti-interferon-γ-neutralizing autoantibodies were detected in the serum, and acquired immunodeficiency was suspected to be the etiology. Antimicrobial chemotherapy was initiated, and the lesions generally regressed. However, only the skull lesions worsened, requiring local resection to control the disease. Currently, the patient is continuing to receive drug therapy with good disease control after debridement.

Sphingolipid-Induced Bone Regulation and Its Emerging Role in Dysfunction Due to Disease and Infection

The human skeleton is a metabolically active system that is constantly regenerating via the tightly regulated and highly coordinated processes of bone resorption and formation. Emerging evidence reveals fascinating new insights into the role of sphingolipids, including sphingomyelin, sphingosine, ceramide, and sphingosine-1-phosphate, in bone homeostasis. Sphingolipids are a major class of highly bioactive lipids able to activate distinct protein targets including, lipases, phosphatases, and kinases, thereby conferring distinct cellular functions beyond energy metabolism. Lipids are known to contribute to the progression of chronic inflammation, and notably, an increase in bone marrow adiposity parallel to elevated bone loss is observed in most pathological bone conditions, including aging, rheumatoid arthritis, osteoarthritis, and osteomyelitis. Of the numerous classes of lipids that form, sphingolipids are considered among the most deleterious. This review highlights the important primary role of sphingolipids in bone homeostasis and how dysregulation of these bioactive metabolites appears central to many chronic bone-related diseases. Further, their contribution to the invasion, virulence, and colonization of both viral and bacterial host cell infections is also discussed. Many unmet clinical needs remain, and data to date suggest the future use of sphingolipid-targeted therapy to regulate bone dysfunction due to a variety of diseases or infection are highly promising. However, deciphering the biochemical and molecular mechanisms of this diverse and extremely complex sphingolipidome, both in terms of bone health and disease, is considered the next frontier in the field.

Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Anticytokine autoantibodies can cause immunodeficiency or dysregulate immune responses. They may phenocopy genetically defined primary immunodeficiencies. We review current anti-type 1 and anti-type 2 interferon; anti-IL-12/23, anti-IL-17, and anti-GM-CSF autoantibodies; HLA associations; disease associations; and mechanistically based treatment options. Suspecting the presence of these autoantibodies in patients and identifying them at the onset of symptoms should ameliorate disease and improve outcomes.

Retrospective Analysis of 10 Cases of Disseminated Nontuberculous Mycobacterial Disease with Osteolytic Lesions

Purpose

Disseminated nontuberculous mycobacterial (DNTM) infection can involve multiple organs, including the lungs, skin and soft tissues and lymph nodes. However, NTM infection leading to osteolysis has been rarely reported. Here, we analyzed the clinical features, osteolytic mechanisms, treatment and prognosis of patients with DNTM disease with osteolytic lesions.

Patients and Methods

This retrospective study was conducted between January 1, 2011, and December 31, 2020, at the First Affiliated Hospital of Guangxi Medical University and the Fourth People’s Hospital of Nanning City. Patients who had culture and/or histopathological proof of DNTM disease with osteolytic lesions were included.

Results

Ten HIV-negative patients with DNTM disease with osteolytic lesions were enrolled. Five of these patients had underlying diseases. Seven and three of the patients were positive and negative for anti-interferon-γ autoantibodies (AIGAs), respectively. The AIGA positivity rate was 70% (7/10). Ostealgia and anemia were the most common symptoms, followed by fever, emaciation, cough, expectoration, anorexia, subcutaneous abscesses and lymphadenopathy. Leukocyte and neutrophil counts were increased. The most common sites were the vertebrae, sternum, clavicle and ribs, although the femur, ilium, humerus, and scapula were also involved. Radiography and computed tomography (CT) showed moth-eaten or irregular destruction of bone, bone defects, pathological fracture, periosteal proliferation and surrounding abscesses. Emission CT (ECT) bone scans showed significantly increased uptake in many skeletal regions. Positron emission tomography(PET)/CT showed metabolic activity in multiple bones. All patients received anti-nontuberculous therapy, and five underwent surgery. Two died during treatment.

Conclusion

DNTM infection of bone and leading to osteolysis usually occurs in patients with AIGA-positive antibodies. DNTM disease with osteolysis is characterized by increased leukocytes and neutrophil counts, focal suppurative granulomas, and multiple areas with moth-eaten or irregular destruction of bone with increased radioactive concentrations. Early diagnosis and timely, effective combination anti-NTM therapy can improve the prognosis.

High Risk of Potential Diarrheagenic Bacillus cereus in Diverse Food Products in Egypt

ABSTRACT

Bacillus cereus is one of the important foodborne pathogens that can be found in various foodstuffs, causes diarrheal and/or emetic syndromes, and can cause severe systemic diseases that may lead to death. This study was conducted to evaluate the prevalence, antimicrobial susceptibility profile, pathogenic potential, and genotypic diversity of B. cereus isolates recovered from diverse food products collected from markets in Cairo, Egypt. Of 165 food samples investigated in this study, 39 (24%) were positive for B. cereus, with contamination levels of 2 to 6 log CFU/g or mL and a higher prevalence of levels >3 log CFU. Antimicrobial susceptibility testing revealed that the B. cereus isolates were fully sensitive to all tested antimicrobial agents except β-lactams. The pathogenic potential of the 39 B. cereus isolates was assessed by detecting and profiling genes encoding virulence factors or toxins: the chromosomal genes hblA, bceT, plc, sph, nheA, entFM, and cytK associated with the diarrheal syndrome and the plasmid ces gene associated with the emetic syndrome. The most frequently detected genes were hblA, nheA, and entFM. All isolates harbored more than one of the diarrheal enterotoxin genes, and the genetic profile hblA-bceT-nheA-entFM-cytK-plc-sph was the most prevalent (20 of 39 isolates). The emetic toxin gene ces was not detected in any isolate. Enterobacterial repetitive intergenic consensus analysis of the 20 B. cereus isolates harboring the most prevalent genetic profile revealed that these isolates were genetically distinct, with a Simpson index of diversity value of 0.989. These findings provide useful information for public health management and serve as a warning of the potential risk of diarrheagenic B. cereus in diverse food products. Therefore, extensive study of the epidemiology of this food pathogen in Egypt is warranted. Strict procedures should be developed to monitor, protect, and safely handle food products, particularly ready-to-eat foodstuffs that are usually consumed without heat treatment.

HIGHLIGHTS

Minireview: Insights into anti-interferon-γ autoantibodies

The association between the presence of anti-interferon-γ autoantibodies and the onset of immunodeficiency with intracellular infections has been clearly established. No standard regimen to control the production of these pathogenic autoantibodies, apart from antimicrobial therapy to eliminate infections, contributes to the medical burden of this syndrome, which sometimes has a fatal outcome. In this review, we summarize the findings on anti-interferon-γ autoantibodies to facilitate further research and to provide guidance for treatment strategies.