Serum albumin and osmolality inhibit Bdellovibrio bacteriovorus predation in human serum

We evaluated the bactericidal activity of Bdellovibrio bacteriovorus, strain HD100, within blood sera against bacterial strains commonly associated with bacteremic infections, including E. coli, Klebsiella pneumoniae and Salmonella enterica. Tests show that B. bacteriovorus HD100 is not susceptible to serum complement or its bactericidal activity. After a two hour exposure to human sera, the prey populations decreased 15- to 7,300-fold due to the serum complement activity while, in contrast, the B. bacteriovorus HD100 population showed a loss of only 33%. Dot blot analyses showed that this is not due to the absence of antibodies against this predator. Predation in human serum was inhibited, though, by both the osmolality and serum albumin. The activity of B. bacteriovorus HD100 showed a sharp transition between 200 and 250 mOsm/kg, and was progressively reduced as the osmolality increased. Serum albumin also acted to inhibit predation by binding to and coating the predatory cells. This was confirmed via dot blot analyses and confocal microscopy. The results from both the osmolality and serum albumin tests were incorporated into a numerical model describing bacterial predation of pathogens. In conclusion, both of these factors inhibit predation and, as such, they limit its effectiveness against pathogenic prey located within sera

Azole-Resistance in Aspergillus terreus and Related Species: An Emerging Problem or a Rare Phenomenon?

Raquel Sabino was not included as an author in the published article. It was corrected a posteriori.Erratum in - Corrigendum: Azole-Resistance in Aspergillus terreus and Related Species: An Emerging Problem or a Rare Phenomenon? [Front Microbiol. 2018] Front Microbiol. 2019 Jan 14;9:3245. doi: 10.3389/fmicb.2018.03245. eCollection 2018.Disponível em: https://www.frontiersin.org/articles/10.3389/fmicb.2018.03245/fullFree PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5882871/ | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340063/Objectives: Invasive mold infections associated with Aspergillus species are a significant cause of mortality in immunocompromised patients. The most frequently occurring aetiological pathogens are members of the Aspergillus section Fumigati followed by members of the section Terrei. The frequency of Aspergillus terreus and related (cryptic) species in clinical specimens, as well as the percentage of azole-resistant strains remains to be studied. Methods: A global set (n = 498) of A. terreus and phenotypically related isolates was molecularly identified (beta-tubulin), tested for antifungal susceptibility against posaconazole, voriconazole, and itraconazole, and resistant phenotypes were correlated with point mutations in the cyp51A gene. Results: The majority of isolates was identified as A. terreus (86.8%), followed by A. citrinoterreus (8.4%), A. hortai (2.6%), A. alabamensis (1.6%), A. neoafricanus (0.2%), and A. floccosus (0.2%). One isolate failed to match a known Aspergillus sp., but was found most closely related to A. alabamensis. According to EUCAST clinical breakpoints azole resistance was detected in 5.4% of all tested isolates, 6.2% of A. terreus sensu stricto (s.s.) were posaconazole-resistant. Posaconazole resistance differed geographically and ranged from 0% in the Czech Republic, Greece, and Turkey to 13.7% in Germany. In contrast, azole resistance among cryptic species was rare 2 out of 66 isolates and was observed only in one A. citrinoterreus and one A. alabamensis isolate. The most affected amino acid position of the Cyp51A gene correlating with the posaconazole resistant phenotype was M217, which was found in the variation M217T and M217V. Conclusions:Aspergillus terreus was most prevalent, followed by A. citrinoterreus. Posaconazole was the most potent drug against A. terreus, but 5.4% of A. terreus sensu stricto showed resistance against this azole. In Austria, Germany, and the United Kingdom posaconazole-resistance in all A. terreus isolates was higher than 10%, resistance against voriconazole was rare and absent for itraconazole.This work was supported by ECMM, ISHAM, and EFISG and in part by an unrestricted research grant through the Investigator Initiated Studies Programof Astellas, MSD, and Pfizer. This study was fundet by the Christian Doppler Laboratory for invasive fungal infections.info:eu-repo/semantics/publishedVersio

Azole-resistance in Aspergillus terreus and related species: An emerging problem or a rare Phenomenon?

Objectives: Invasive mold infections associated with Aspergillus species are a significant cause of mortality in immunocompromised patients. The most frequently occurring aetiological pathogens are members of the Aspergillus section Fumigati followed by members of the section Terrei. The frequency of Aspergillus terreus and related (cryptic) species in clinical specimens, as well as the percentage of azole-resistant strains remains to be studied. Methods: A global set (n = 498) of A. terreus and phenotypically related isolates was molecularly identified (beta-tubulin), tested for antifungal susceptibility against posaconazole, voriconazole, and itraconazole, and resistant phenotypes were correlated with point mutations in the cyp51A gene. Results: The majority of isolates was identified as A. terreus (86.8), followed by A. citrinoterreus (8.4), A. hortai (2.6), A. alabamensis (1.6), A. neoafricanus (0.2), and A. floccosus (0.2). One isolate failed to match a known Aspergillus sp., but was found most closely related to A. alabamensis. According to EUCAST clinical breakpoints azole resistance was detected in 5.4 of all tested isolates, 6.2 of A. terreus sensu stricto (s.s.) were posaconazole-resistant. Posaconazole resistance differed geographically and ranged from 0 in the Czech Republic, Greece, and Turkey to 13.7 in Germany. In contrast, azole resistance among cryptic species was rare 2 out of 66 isolates and was observed only in one A. citrinoterreus and one A. alabamensis isolate. The most affected amino acid position of the Cyp51A gene correlating with the posaconazole resistant phenotype was M217, which was found in the variation M217T and M217V. Conclusions: Aspergillus terreus was most prevalent, followed by A. citrinoterreus. Posaconazole was the most potent drug against A. terreus, but 5.4 of A. terreus sensu stricto showed resistance against this azole. In Austria, Germany, and the United Kingdom posaconazole-resistance in all A. terreus isolates was higher than 10, resistance against voriconazole was rare and absent for itraconazole. © 2018 Zoran, Sartori, Sappl, Aigner, Sánchez-Reus, Rezusta, Chowdhary, Taj-Aldeen, Arendrup, Oliveri, Kontoyiannis, Alastruey-Izquierdo, Lagrou, Cascio, Meis, Buzina, Farina, Drogari-Apiranthitou, Grancini, Tortorano, Willinger, Hamprecht, Johnson, Klingspor, Arsic-Arsenijevic, Cornely, Meletiadis, Prammer, Tullio, Vehreschild, Trovato, Lewis, Segal, Rath, Hamal, Rodriguez-Iglesias, Roilides, Arikan-Akdagli, Chakrabarti, Colombo, Fernández, Martin-Gomez, Badali, Petrikkos, Klimko, Heimann, Uzun, Roudbary, de la Fuente, Houbraken, Risslegger, Lass-Flörl and Lackner

Azole-resistance in Aspergillus terreus and related species: An emerging problem or a rare Phenomenon?

Objectives: Invasive mold infections associated with Aspergillus species are a significant cause of mortality in immunocompromised patients. The most frequently occurring aetiological pathogens are members of the Aspergillus section Fumigati followed by members of the section Terrei. The frequency of Aspergillus terreus and related (cryptic) species in clinical specimens, as well as the percentage of azole-resistant strains remains to be studied. Methods: A global set (n = 498) of A. terreus and phenotypically related isolates was molecularly identified (beta-tubulin), tested for antifungal susceptibility against posaconazole, voriconazole, and itraconazole, and resistant phenotypes were correlated with point mutations in the cyp51A gene. Results: The majority of isolates was identified as A. terreus (86.8), followed by A. citrinoterreus (8.4), A. hortai (2.6), A. alabamensis (1.6), A. neoafricanus (0.2), and A. floccosus (0.2). One isolate failed to match a known Aspergillus sp., but was found most closely related to A. alabamensis. According to EUCAST clinical breakpoints azole resistance was detected in 5.4 of all tested isolates, 6.2 of A. terreus sensu stricto (s.s.) were posaconazole-resistant. Posaconazole resistance differed geographically and ranged from 0 in the Czech Republic, Greece, and Turkey to 13.7 in Germany. In contrast, azole resistance among cryptic species was rare 2 out of 66 isolates and was observed only in one A. citrinoterreus and one A. alabamensis isolate. The most affected amino acid position of the Cyp51A gene correlating with the posaconazole resistant phenotype was M217, which was found in the variation M217T and M217V. Conclusions: Aspergillus terreus was most prevalent, followed by A. citrinoterreus. Posaconazole was the most potent drug against A. terreus, but 5.4 of A. terreus sensu stricto showed resistance against this azole. In Austria, Germany, and the United Kingdom posaconazole-resistance in all A. terreus isolates was higher than 10, resistance against voriconazole was rare and absent for itraconazole. © 2018 Zoran, Sartori, Sappl, Aigner, Sánchez-Reus, Rezusta, Chowdhary, Taj-Aldeen, Arendrup, Oliveri, Kontoyiannis, Alastruey-Izquierdo, Lagrou, Cascio, Meis, Buzina, Farina, Drogari-Apiranthitou, Grancini, Tortorano, Willinger, Hamprecht, Johnson, Klingspor, Arsic-Arsenijevic, Cornely, Meletiadis, Prammer, Tullio, Vehreschild, Trovato, Lewis, Segal, Rath, Hamal, Rodriguez-Iglesias, Roilides, Arikan-Akdagli, Chakrabarti, Colombo, Fernández, Martin-Gomez, Badali, Petrikkos, Klimko, Heimann, Uzun, Roudbary, de la Fuente, Houbraken, Risslegger, Lass-Flörl and Lackner

Corrigendum: Azole-resistance in aspergillus terreusand related species: An emerging problem or a rare phenomenon? (Frontiers in Microbiology (2018) 9 (516) DOI: 10.3389/fmicb.2018.00516)

Raquel Sabino was not included as an author in the published article. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated. © 2019 Zoran, Sartori, Sappl, Aigner, Sánchez-Reus, Rezusta, Chowdhary, Taj-Aldeen, Arendrup, Oliveri, Kontoyiannis, Alastruey-Izquierdo, Lagrou, Lo Cascio, Meis, Buzina, Farina, Drogari-Apiranthitou, Grancini, Tortorano, Willinger, Hamprecht, Johnson, Klingspor, Arsic-Arsenijevic, Cornely, Meletiadis, Prammer, Tullio, Vehreschild, Trovato, Lewis, Segal, Rath, Hamal, Rodriguez-Iglesias, Roilides, Arikan-Akdagli, Chakrabarti, Colombo, Fernández, Martin-Gomez, Badali, Petrikkos, Klimko, Heimann, Uzun, Roudbary, de la Fuente, Houbraken, Risslegger, Sabino, Lass-Flörl and Lackner

Zygomycosis in immunocompromised non-haematological patients

Zygomycoses caused by fungi of the mucorales order (mucormycoses) are emerging fungal diseases with a high fatality rate. The most important risk factors include neutropenia or functional neutropenia, diabetic ketoacidosis, iron overload, major trauma, prolonged use of corticosteroids, illicit intravenous drug (ID) use, neonatal prematurity, malnourishment, and maybe a previous exposure to antifungal agents with no activity against zygomycetes, such as voriconazole and echinocandins. A high index of suspicion is crucial for the diagnosis, as prompt and appropriate management can considerably reduce morbidity and mortality. Suspicion index can be increased through recognition of the differential patterns of clinical presentation. In the non- haematological immunocompromised patients, mucormycosis can manifest in various clinical forms, depending on the underlying condition: mostly as rhino-orbital or rhino-cerebral in diabetes patients, pulmonary infection in patients with malignancy or solid organ transplantation, disseminated infection in iron overloaded or deferoxamine treated patients, cerebral - with no sinus involvement - in ID users, gastrointestinal in premature infants or malnourishment, and cutaneous after direct inoculation in immunocompetent individuals with trauma or burns. Treating a patient's underlying medical condition and reducing immunosuppression are essential to therapy. Rapid correction of metabolic abnormalities is mandatory in cases such as uncontrolled diabetes, and corticosteroids or other immunosuppressive drugs should be discontinued where feasible. AmphotericinB or its newer and less toxic lipid formulations are the drugs of choice regarding antifungal chemotherapy, while extensive surgical debridement is essential to reduce infected and necrotic tissue. A high number of cases could be prevented through measures including diabetes control programmes and proper pre- and post-surgical hygiene

Epidemiology and diagnosis of mucormycosis: An update

Mucormycosis is an angioinvasive fungal infection, due to fungi of the order Mucorales. Its incidence cannot be measured exactly, since there are few population-based studies, but multiple studies have shown that it is increasing. The prevalence of mucormycosis in India is about 80 times the prevalence in developed countries, being approximately 0.14 cases per 1000 population. Diabetes mellitus is the main underlying disease globally, especially in low and middle-income countries. In developed countries the most common underlying diseases are hematological malignancies and transplantation. The epidemiology of mucormycosis is evolving as new immunomodulating agents are used in the treatment of cancer and autoimmune diseases, and as the modern diagnostic tools lead to the identification of previously uncommon genera/species such as Apophysomyces or Saksenaea complex. In addition, new risk factors are reported from Asia, including post-pulmonary tuberculosis and chronic kidney disease. New emerging species include Rhizopus homothallicus, Thamnostylum lucknowense, Mucor irregularis and Saksenaea erythrospora. Diagnosis of mucormycosis remains challenging. Clinical approach to diagnosis has a low sensitivity and specificity, it helps however in raising suspicion and prompting the initiation of laboratory testing. Histopathology, direct examination and culture remain essential tools, although the molecular methods are improving. The internal transcribed spacer (ITS) region is the most widely sequenced DNA region for fungi and it is recommended as a first-line method for species identification of Mucorales. New molecular platforms are being investigated and new fungal genetic targets are being explored. Molecular-based methods have gained acceptance for confirmation of the infection when applied on tissues. Methods on the detection of Mucorales DNA in blood have shown promising results for earlier and rapid diagnosis and could be used as screening tests in high-risk patients, but have to be validated in clinical studies. More, much needed, rapid methods that do not require invasive procedures, such as serology-based point-of-care, or metabolomics-based breath tests, are being developed and hopefully will be evaluated in the near future. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Rare fungal infectious agents: A lurking enemy

In the expanding population of immunocompromised patients and those treated in intensive care units, rare fungal infectious agents have emerged as important pathogens, causing invasive infections associated with high morbidity and mortality. These infections may present either as de novo or as breakthrough invasive infections in high-risk patients with hematologic malignancies receiving prophylactic or empirical antifungal therapy or in patients with central venous catheters. Diagnosis and treatment are challenging. Physicians should have a high index of suspicion because early diagnosis is of paramount importance. Conventional diagnostic methods such as cultures and histopathology are still essential, but rapid and more specific molecular techniques for both detection and identification of the infecting pathogens are being developed and hopefully will lead to early targeted treatment. The management of invasive fungal infections is multimodal. Reversal of risk factors, if feasible, should be attempted. Surgical debridement is recommended in localized mold infections. The efficacy of various antifungal drugs is not uniform. Amphotericin B is active against most yeasts, except Trichosporon, as well as against Mucorales, Fusarium, and some species of Paecilomyces and dimorphic fungi. The use of voriconazole is suggested for the treatment of trichosporonosis and scedosporiosis. Combination treatment, though recommended as salvage therapy in some infections, is controversial in most cases. Despite the use of available antifungals, mortality remains high. The optimization of molecular-based techniques, with expansion of reference libraries and the possibility for direct detection of resistance mechanisms, is awaited with great interest in the near future. Further research is necessary, however, in order to find the best ways to confront and destroy these lurking enemies. © 2017 Skiada A et al

Epidemiology of mucormycosis in Europe

Zygomycosis (mucormycosis) is being increasingly recognized as causing infection in recent years. National and multinational European surveys attempting to analyse the epidemiological parameters of this potentially devastating infection are very few. Although the exact incidence could not be defined due to the different methodologies used in these studies and the absence of a denominator, there were some useful observations made regarding the clinical presentation, sites of infection and diagnostic practices. Moreover, the importance for a prompt and accurate diagnosis has been stressed. As early diagnosis can significantly affect the initiation of treatment and decrease mortality, future research should focus on the development of an epidemiological risk assessment tool and novel diagnostic methods. © 2014 The Authors. Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases