Three-dimensional lung parenchyma model for studies of Aspergillus fumigatus infection and antifungal treatment.

Aim: This work aims to standardize the three-dimensional hydroxyethyl-alginate-gelatin (HAG) scaffold as a model to evaluate Aspergillus fumigatus biofilm and antifungal treatments. Methods: The scaffold was characterized by physical, rheological and microscopic analyses; the antibiofilm action was evaluated by determination of cfu and metabolic activity. Results: The scaffold was non-toxic showing stability in aqueous media, swelling capacity, elasticity and had homogeneously distributed pores averaging 190 µm. The A. fumigatus biofilm established itself very well on the scaffold and treatment with amphotericin B and voriconazole reduced viable cells and metabolic activity. Conclusion: The HAG scaffold proved to be a model to mimic lung parenchyma, suitable for establishing a 3D biofilm culture of A. fumigatus and evaluating the efficacy of antifungals.

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Surgical Technique of Central and Over-the-Top Full-Endoscopic Decompression of the Cervical Spine: A Technical Note.

Endoscopic surgery of the cervical spine is constantly evolving and the spectrum of its indications has expanded in recent decades. Full-endoscopic techniques have standardized the procedures for posterior and anterior access. The full-endoscopic approach was developed to treat degenerative diseases with the least possible invasion and without causing instability of the cervical spine. The posterior full-endoscopic approach is indicated for the treatment of diseases of the lateral part of the vertebral segment, such as herniations and stenoses of the lateral recess and vertebral foramen. There has been little discussion of this approach to the treatment of central stenosis of the cervical spine. This technical note describes a step-by-step surgical technique for central and over-the-top full-endoscopic decompression in the cervical spine, using a 3.7 mm working channel endoscope. This technique has already been shown to be effective in a recent case series with a 4.7 mm working channel endoscope, and may represent a new treatment option for central or bilateral lateral recess stenosis. There is also the possibility of a bilateral full-endoscopic approach, but this may be associated with greater muscle damage and a longer operative time. Case series and comparative studies should be encouraged to confirm the safety and utility of this technique.

Experimental models for pharmacokinetic and pharmacodynamic studies of antifungals used in cryptococcosis treatment.

Studies on cryptococcosis in the mammal animal model have demonstrated the occurrence of central nervous system infection and similarities in fungal pathogenicity with clinical and immunological features of the human infection. Although there is still a lack of studies involving pharmacokinetics (PK) and pharmacodynamics (PD) in animal models of cryptococcosis in the literature, these experimental models are useful for understanding this mycosis and antifungal effectiveness in improving the therapeutic schemes. The scope of this review is to describe and discuss the main mammal animal models for PK and PD studies of antifungals used in cryptococcosis treatment. Alternative models and computational methods are also addressed. All approaches for PK/PD studies are relevant to investigating drug-infection interaction and improving cryptococcosis therapy.

Antifungal drugs: An updated review of central nervous system pharmacokinetics.

Invasive fungal infections (IFIs) in the central nervous system (CNS) are particularly hard to treat and are associated with high morbidity and mortality rates. Four chemical classes of systemic antifungal agents are used for the treatment of IFIs (eg meningitis), including polyenes, triazoles, pyrimidine analogues and echinocandins. This review will address all of these classes and discuss their penetration and accumulation in the CNS. Treatment of fungal meningitis is based on the antifungal that shows good penetration and accumulation in the CNS. Pharmacokinetic data concerning the entry of antifungal agents into the intracranial compartments are faulty. This review will provide an overview of the ability of systemic antifungals to penetrate the CNS, based on previously published drug physicochemical properties and pharmacokinetic data, for evaluation of the most promising antifungal drugs for the treatment of fungal CNS infections. The studies selected and discussed in this review are from 1990 to 2019.

New Approaches for Cryptococcosis Treatment.

Cryptococcosis is an important opportunistic infection and a leading cause of meningitis in patients with HIV infection. The antifungal pharmacological treatment is limited to amphotericin B, fluconazole and 5- flucytosine. In addition to the limited pharmacological options, the high toxicity, increased resistance rate and difficulty of the currently available antifungal molecules to cross the blood-brain barrier hamper the treatment. Thus, the search for new alternatives for the treatment of cryptococcal meningitis is extremely necessary. In this review, we describe the therapeutic strategies currently available, discuss new molecules with antifungal potential in different phases of clinical trials and in advanced pre-clinical phase, and examine drug nanocarriers to improve delivery to the central nervous system.

Molecular types of Cryptococcus species isolated from patients with cryptococcal meningitis in a Brazilian tertiary care hospital.

There are limited data on the molecular epidemiology of cryptococcosis in Brazil. Here, we report on the identification of the molecular pattern of the Cryptococcus species that caused meningitis in patients admitted in a Brazilian reference tertiary care hospital, and review the published studies addressing the molecular epidemiology of Cryptococcus in Brazil. Our study has shown the predominance of molecular type VNII in HIV-infected patients with cryptococcal meningoencephalitis. Molecular types VNII and VGII were occasionally detected in HIV-infected and non-infected patients with meningoencephalitis. In contrast, previous studies have shown that several regions exhibited a high prevalence of the VNI molecular type and sporadic cases of the VNII and VGII molecular types in patients with cryptococcosis in Brazil. Additional studies including VNII isolates will contribute to understanding the epidemiology and phylogenetic relationship of these genotype compared to the other ones. So far, no clear correlation has been established between genotypes, antifungal susceptibility for Cryptococcus and clinical outcome in cryptococcosis.

Molecular types of Cryptococcus species isolated from patients with cryptococcal meningitis in a Brazilian tertiary care hospital

ABSTRACT There are limited data on the molecular epidemiology of cryptococcosis in Brazil. Here, we report on the identification of the molecular pattern of the Cryptococcus species that caused meningitis in patients admitted in a Brazilian reference tertiary care hospital, and review the published studies addressing the molecular epidemiology of Cryptococcus in Brazil. Our study has shown the predominance of molecular type VNII in HIV-infected patients with cryptococcal meningoencephalitis. Molecular types VNII and VGII were occasionally detected in HIV-infected and non-infected patients with meningoencephalitis. In contrast, previous studies have shown that several regions exhibited a high prevalence of the VNI molecular type and sporadic cases of the VNII and VGII molecular types in patients with cryptococcosis in Brazil. Additional studies including VNII isolates will contribute to understanding the epidemiology and phylogenetic relationship of these genotype compared to the other ones. So far, no clear correlation has been established between genotypes, antifungal susceptibility for Cryptococcus and clinical outcome in cryptococcosis.

Relationship between intracranial pressure and antifungal agents levels in the CSF of patients with cryptococcal meningitis.

The purpose of this study was to evaluate the influence of intracranial hypertension in the cerebrospinal fluid (CSF) levels of amphotericin B and fluconazole levels of patients with cryptococcal meningitis. CSF samples and intracranial pressure were obtained by means of routine punctures performed at days 1, 7, and 14 of therapy, respectively. Amphotericin B and fluconazole CSF levels were measured by HPLC method as previously described. The minimum inhibitory concentration for amphotericin B, fluconazole, 5΄flucytosine, and voriconazole of each Cryptococcus isolate was performed according to CLSI. The predominant Cryptococcus species found was C. neoformans, and the major underlying condition was AIDS. Only one CSF sample had a detectable level for amphotericin B during the 14 days of therapy. Fluconazole CSF levels progressively increased from day 1 to day 14 of therapy for most cases. Fluconazole levels in the CSF were above the minimum inhibitory concentrations (MICs) for Cryptococcus during the initial 14 days of antifungal therapy. Variations of intracranial pressure did not affect amphotericin B and fluconazole levels in the CSF. The generalized estimating correlation (GEE) and Spearman correlation test (SCT) showed no significant correlation between the amphotericin B or fluconazole concentrations in the CSF and intracranial pressure (P = .953 and P = .093, respectively for GEE test and P = .477 and P = .847, respectively, for SCT). Combination therapy of amphotericin B with fluconazole was effective in 60% of the patients considering CSF cultures were negative in 9 of 15 patients after 14 days of therapy. Further studies are necessary to evaluate the role of intracranial hypertension on the therapeutic efficacy of different antifungal agents in patients with cryptococcal meningitis.

Animal Models and Antifungal Agents in Paracoccidioidomycosis: An Overview.

Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis, the most prevalent systemic mycosis in Latin America. The morbidity and mortality associated with paracoccidioidomycosis necessitate our understanding of fungal pathogenesis and discovering of new agents to treat this infection. Animal models have contributed much to the knowledge of fungal infections and their corresponding therapeutic treatments. This is true for animal models of the primary fungal pathogens such as P. brasiliensis. This review describes the development, details and utility of animal models of paracoccidioidomycosis for studying and developing the current antifungal agents used for therapy of this fungal disease and novel agents with antifungal properties against P. brasiliensis.

Epidemiology of Rhodotorula: an emerging pathogen.

This is an updated paper focusing on the general epidemiological aspects of Rhodotorula in humans, animals, and the environment. Previously considered nonpathogenic, Rhodotorula species have emerged as opportunistic pathogens that have the ability to colonise and infect susceptible patients. Rhodotorula species are ubiquitous saprophytic yeasts that can be recovered from many environmental sources. Several authors describe the isolation of this fungus from different ecosystems, including sites with unfavourable conditions. Compared to R. mucilaginosa, R. glutinis and R. minuta are less frequently isolated from natural environments. Among the few references to the pathogenicity of Rhodotorula spp. in animals, there are several reports of an outbreak of skin infections in chickens and sea animals and lung infections and otitis in sheep and cattle. Most of the cases of infection due to Rhodotorula in humans were fungemia associated with central venous catheter (CVC) use. The most common underlying diseases included solid and haematologic malignancies in patients who were receiving corticosteroids and cytotoxic drugs, the presence of CVC, and the use of broad-spectrum antibiotics. Unlike fungemia, some of the other localised infections caused by Rhodotorula, including meningeal, skin, ocular, peritoneal, and prosthetic joint infections, are not necessarily linked to the use of CVCs or immunosuppression.

Experimental Rhodotorulosis infection in rats.

The low pathogenicity of Rhodotorula spp. is probably related to its reduced ability to grow at 37 °C, an attribute typically enhancing virulence of pathogenic strains. Animal experimentation is a valuable tool to study the pathogenesis of unusual human mycosis, such as Rhodotorula infection. The authors describe the first experimental model of disseminated Rhodotorula infection described in the literature and comment the relevant histopathologic aspects of the infection. Our results showed that the most affected organs by R. mucilaginosa were the lungs, spleen, and especially the liver which presented severe degree of infection. Considering the animals were highly immunocompromised, histopathology of the involved affected organs revealed few epithelioid cells and multinuclear giant cells in association with abundant yeast forms with occasional granuloma formation.

Continuous infusion of amphotericin B deoxycholate: an innovative, low-cost strategy in antifungal treatment.

The combination of amphotericin B and sodium deoxycholate is the formulation most used in clinical practice. The development of new agents such as amphotericin with lipid formulations, caspofungin, voriconazole and other azolic derivatives, promoted alternatives to amphotericin B deoxycholate. However, because of the high cost of these new drugs, their use is difficult in a scenario of limited resources. A few strategies have been devised to make the use of amphotericin B deoxycholate less toxic. In this review, we seek to describe the accumulated knowledge about this molecule, with focus on its use in continuous infusion, which appears to be an alternative to reduce toxicity, while maintaining its clinical efficacy.

Metallo-â-lactamase-producing Pseudomonas aeruginosa in two hospitals from southern Brazil

This study determined the prevalence of metallo-â-lactamase (MBL)-producing Pseudomonas aeruginosa in two hospitals located in the Southern part of Brazil and compare the performance of two different phenotypic tests. Thirty-one non-repetitive Pseudomonas aeruginosa isolates from various clinical samples from patients admitted to two hospitals located in Rio Grande do Sul, Brazil (twenty-three from a hospital in Porto Alegre City and eight isolates from a hospital in Vale dos Sinos Region). All strains suggestive of possessing MBLs by phenotypic methods were included in this study. Phenotypic detection of MBLs was carried out simultaneously by using both the MBL Etest® and disk approximation test using 2-mercaptopropionic acid close to a ceftazidime disk. Strains positive were further confirmed using molecular techniques for blaVIM, blaIMP and blaSPM-1. The prevalence of MBLs from samplesof inpatients from the hospital located in Porto Alegre was 30.4 percent and that of inpatients from Vale dos Sinos hospital was only 3.1 percent. Only MBL type SPM-1 was detected in these samples by molecular analysis and all were detected by the Etest® MBL strips. The prevalence of P. aeruginosa that produce MBLs can be markedly different in distinct geographical areas, even among different hospitals in the same area. In our study, the EDTA-based method was the only method able to detect all strains harboring the SPM-1 enzyme.

Metallo-beta-lactamase-producing Pseudomonas aeruginosa in two hospitals from southern Brazil.

This study determined the prevalence of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa in two hospitals located in the Southern part of Brazil and compare the performance of two different phenotypic tests. Thirty-one non-repetitive Pseudomonas aeruginosa isolates from various clinical samples from patients admitted to two hospitals located in Rio Grande do Sul, Brazil (twenty-three from a hospital in Porto Alegre City and eight isolates from a hospital in Vale dos Sinos Region). All strains suggestive of possessing MBLs by phenotypic methods were included in this study. Phenotypic detection of MBLs was carried out simultaneously by using both the MBL Etest and disk approximation test using 2-mercaptopropionic acid close to a ceftazidime disk. Strains positive were further confirmed using molecular techniques for bla(VIM), bla(IMP) and bla(SPM-1). The prevalence of MBLs from samples of inpatients from the hospital located in Porto Alegre was 30.4% and that of inpatients from Vale dos Sinos hospital was only 3.1%. Only MBL type SPM-1 was detected in these samples by molecular analysis and all were detected by the Etest MBL strips. The prevalence of P. aeruginosa that produce MBLs can be markedly different in distinct geographical areas, even among different hospitals in the same area. In our study, the EDTA-based method was the only method able to detect all strains harboring the SPM-1 enzyme.