Epidemiology and Host Factors

The emerging links between immunosenescence in innate immune system and neurocryptococcosis

Immunosenescence refers to the age-related progressive decline of immune function contributing to the increased susceptibility to infectious diseases in older people. Neurocryptococcosis, an infectious disease of central nervous system (CNS) caused by Cryptococcus neoformans (C. Neoformans) and C. gattii, has been observed with increased frequency in aged people, as result of the reactivation of a latent infection or community acquisition. These opportunistic microorganisms belonging to kingdom of fungi are capable of surviving and replicating within macrophages. Typically, cryptococcus is expelled by vomocytosis, a non-lytic expulsive mechanism also promoted by interferon (IFN)-I, or by cell lysis. However, whereas in a first phase cryptococcal vomocytosis leads to a latent asymptomatic infection confined to the lung, an enhancement in vomocytosis, promoted by IFN-I overproduction, can be deleterious, leading the fungus to reach the blood stream and invade the CNS. Cryptococcus may not be easy to diagnose in older individuals and, if not timely treated, could be potentially lethal. Therefore, this review aims to elucidate the putative causes of the increased incidence of cryptococcal CNS infection in older people discussing in depth the mechanisms of immunosenscence potentially able to predispose to neurocryptococcosis, laying the foundations for future research. A deepest understanding of this relationship could provide new ways to improve the prevention and recognition of neurocryptococcosis in aged frail people, in order to quickly manage pharmacological interventions and to adopt further preventive measures able to reduce the main risk factors.

Cutaneous Manifestations of Mycobacterium tuberculosis: A Literature Review

Tuberculosis is an ancient disease that humanity struggled with for centuries and continues to struggle with. The bacteria Mycobacterium tuberculosis often infects the lungs through respiratory transmission and manifests itself through various symptoms, including cutaneous infections. Cutaneous tuberculosis (CTB) comprises about 1% to 1.5% of all extrapulmonary manifestations and is often accompanied by polymorphous lesions, including papules, nodules, plaques, ulcers, gummas, and verrucous lesions. CTB is most commonly observed in low-income, HIV, and immunosuppressed populations, similar to intrapulmonary manifestations. The main pathogen for CTB is M. tuberculosis but less commonly with M. bovis and BCG vaccine, and the modes of transmission are largely classified into exogenous and endogenous CTB. Current treatment options for CTB include oral therapy of antibiotic medications such as rifampicin, streptomycin, ethambutol, isoniazid, and pyrazinamide, which is occasionally combined with surgical intervention.

INSIGHTS INTO THERAPEUTIC LIQUID MIXTURES AND FORMULATIONS TOWARDS TUBERCULOSIS THERAPY

Therapeutic liquid mixtures, as deep eutectic systems, are considered a sustainable strategy that can be useful for the modification and enhancement of the pharmacokinetics and pharmacodynamics of different active ingredients. In this study, we assessed the stability and antibacterial activity of therapeutic liquid formulations prepared with anti-tuberculosis drugs. Tuberculosis therapy presents various pitfalls related, for example, to the administration of prolonged regimens of multiple drugs, different severe adverse effects, low compliance of the patient to treatment and the development of drug resistance. During this study, it was possible to assess the physicochemical stability of the formulations for 6 months, by polarized optical microscopy, ¹H-NMR and FTIR-ATR. Furthermore, the mixtures present an antibacterial effect against a drug-susceptible Mycobacterium tuberculosis strain (H37Rv). This was particularly evident for the mixtures with ethambutol incorporated, making them interesting to pursue with further studies and evaluation of clinical applicability. Upon infection, it was also observed that a single and higher dose appears to be more effective than lower separate doses, which could allow the production of patient-friendly formulations.

Psychological stress creates an immune suppressive environment in the lung that increases susceptibility of aged mice to Mycobacterium tuberculosis infection

Age is a major risk factor for chronic infections, including tuberculosis (TB). Elderly TB patients also suffer from elevated levels of psychological stress. It is not clear how psychological stress impacts immune response to Mycobacterium tuberculosis (M.tb). In this study, we used social disruption stress (SDR) to investigate effects of psychological stress in young and old mice. Unexpectedly, we found that SDR suppresses lung inflammation in old mice as evidenced by lower pro-inflammatory cytokine levels in bronchial lavage fluid and decreased cytokine mRNA expression by alveolar macrophages. To investigate effects of stress on M.tb infection, mice were subjected to SDR and then infected with M.tb. As previously reported, old mice were better at controlling infection at 30 days than young mice. This control was transient as CFUs at 60 days were higher in old control mice compared to young mice. Consistently, SDR significantly increased M.tb growth at 60 days in old mice compared to young mice. In addition, SDR in old mice resulted in accumulation of IL-10 mRNA and decreased IFN-γ mRNA at 60 days. Also, confocal microscopy of lung sections from old SDR mice showed increased number of CD4 T cells which express LAG3 and CD49b, markers of IL-10 secreting regulatory T cells. Further, we also demonstrated that CD4 T cells from old SDR mice express IL-10. Thus, we conclude that psychological stress in old mice prior to infection, increases differentiation of IL-10 secreting T cells, which over time results in loss of control of the infection.

The clinical characteristics and therapeutic outcomes of cryptococcal meningitis in elderly patients: a hospital-based study

BACKGROUND

The elderly, and especially those with an immuno-compromised status, are vulnerable to infectious diseases. The purpose of this study was to examine the clinical characteristics and therapeutic outcomes of cryptococcal meningitis (CM) in elderly patients in Taiwan.

METHODS

Ninety-nine adult patients with CM were identified during a 15-year study period (2002-2016), of whom 38 elderly (≥ 65 years) patients (16 men and 22 women, median age 72.9 years; range 65-86 years) were included for analysis. The clinical characteristics and therapeutic outcomes of these patients were analyzed and compared to non-elderly adult patients (< 65 years) with CM.

RESULTS

Among the 38 patients, diabetes mellitus was the most common underlying condition (15), followed by adrenal insufficiency (7), malignancy (6), hematologic disorders (5), chronic obstructive pulmonary disease (5), autoimmune diseases (3), liver cirrhosis (3) and acquired immunodeficiency syndrome (1). Altered consciousness (29), fever (21) and headache (17) were the leading clinical manifestations. Positive cerebrospinal fluid and blood cultures for Cryptococcus (C.) neoformans were found in 26 and 9 patients, respectively. There were significant differences in gender, altered consciousness and recent cerebral infarction between the elderly and non-elderly groups. The elderly group had a high mortality rate (36.8%, 14/38), and the presence of cryptococcemia was the most significant prognostic factor.

CONCLUSIONS

This study offers a preliminary view of the clinical characteristics of CM in the elderly. The results suggest that elderly patients (≥ 65 years) are more vulnerable to CM than adults aged < 65 years. Compared to the non-elderly group, the elderly group had female predominance, higher rates of altered consciousness and recent cerebral infarction as the clinical presentation. The presence of cryptococcemia was a significant prognostic factor in the elderly group. This study is limited by the small number of patients, and further large-scale studies are needed to better delineate this specific infectious syndrome.

Tuberculosis of the Oral Cavity Misdiagnosed as Precancerous Lesion

Introduction

The aim of this case report was to discuss an extremely rare oral lesion as a result of primary pulmonary tuberculosis.

Case report

In this case report, the patient with refractory painless ulceration at ventral surface of the tongue was described. Detailed medical history was taken followed by clinical examination of the oral mucosa and palpation of regional lymph nodes. Clinical examination revealed ulceration on the patient’s ventro-lateral surface of the tongue, approximately two centimeters in diameter. Palpation of regional lymph nodes has not revealed enlargement. The toluidine blue test of the suspected lesion was performed at each control examination. Biopsy samples for histopathologic diagnosis were taken three times. The analysis of the first biopsy sample for histopathology revealed a non-specific inflammation, the second biopsy revealed a caseous necrosis without positive Ziehl-Neelsen staining and the third biopsy revealed a granulomatous inflammation which was highly suspicious of sarcoidosis. During hospitalization, the patient underwent a complete physical examination, and laboratory and radiological diagnostics. Physical chest examination revealed bilaterally coarse crepitations and laboratory findings of his complete blood count revealed normocytic anemia of chronic disease. Radiographic examination of lungs showed multiple small nodules bilaterally and positive direct sputum smear.

Conclusion

Although oral tuberculosis is a rare condition, it must be taken into account in differential diagnosis of refractory painless oral ulcers.

Screening for Diabetes Mellitus among Tuberculosis Patients: Findings from a Study at a Tertiary Hospital in Lusaka, Zambia

BACKGROUND

Diabetes mellitus (DM) is known to be associated with active tuberculosis (TB). Zambia is a low-income sub-Saharan African country with a high TB burden and increasing numbers of newly diagnosed DM patients.

MATERIALS AND METHODS

This was an observational study conducted at the University Teaching Hospital in Lusaka, Zambia, from October 2014 to February 2016. Adult patients with active TB were screened for DM.

RESULTS

A total of 127 individuals were enrolled in the study. Six patients (5%) were found to have diabetes. Of these, three had a prior diagnosis of diabetes and were on medication while three were newly diagnosed. Low education level was significantly associated with DM (p=0.001; 95% CI 0.001-0.148).

CONCLUSION

The prevalence of DM among individuals with smear positive TB in our study population was similar to that of the general population in Zambia.