A prospective international Aspergillus terreus survey: an EFISG, ISHAM and ECMM joint study.

OBJECTIVES: A prospective international multicentre surveillance study was conducted to investigate the prevalence and amphotericin B susceptibility of Aspergillus terreus species complex infections. METHODS: A total of 370 cases from 21 countries were evaluated. RESULTS: The overall prevalence of A. terreus species complex among the investigated patients with mould-positive cultures was 5.2% (370/7116). Amphotericin B MICs ranged from 0.125 to 32 mg/L, (median 8 mg/L). CONCLUSIONS: Aspergillus terreus species complex infections cause a wide spectrum of aspergillosis and the majority of cryptic species display high amphotericin B MICs.

An estimate of the burden of serious fungal diseases in Greece.

Data on the epidemiology of serious fungal infections in Greece are scarce. Our aim was to calculate the burden of serious fungal diseases in Greece. A thorough literature search for papers reporting epidemiological data on serious fungal diseases in Greece was performed. Where no Greek data existed, we used a structured set of assumptions to estimate fungal disease burden, based on specific high-risk populations. Of the 10.8 million population, 85.5 % are adults and 27 % are over 60 years of age. The annual fungal disease estimates are as follows: 142,337 Greek women get recurrent vaginal thrush (2,632 cases/100,000 females); there are 889 cases of esophageal candidiasis (8.2 cases/100,000); annual incidence of Pneumocystis pneumonia is 112 cases; chronic pulmonary aspergillosis prevalence is 386 cases; there are 20,843 patients with allergic bronchopulmonary aspergillosis and 27,744 with severe asthma with fungal sensitization; candidaemia incidence is 541 cases (5.0/100,000); there are 81 cases of Candida peritonitis; invasive aspergillosis occurs in 1,125 patients. According to our calculations, 194,067 individuals (1.79 cases/100,000) in Greece suffer from serious fungal diseases each year. This is the first attempt to determine the burden of fungal diseases in Greece, and provides a crude estimate on its impact on public health.

European Confederation of Medical Mycology (ECMM) epidemiological survey on invasive infections due to Fusarium species in Europe.

In order to better understand the epidemiology of fusariosis in Europe, a survey collecting information on the clinical characteristics of the patients infected by Fusarium as well as on the infecting isolates was launched. A total of 76 cases of invasive fusariosis occurring from January 2007 to June 2012 were collected and Fusarium isolates were identified by sequencing the translation elongation factor 1α (TEF) gene. Also, antifungal susceptibility was tested by broth microdilution according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Etest. Disseminated disease was considered proven in 46 cases and probable in 17 cases. Localised infection was seen in 13 cases. Gibberella fujikuroi species complex (SC), including Fusarium verticillioides and F. proliferatum, and F. solani SC were the most frequent aetiology of disseminated and localised infections, respectively. The crude mortality rate was 46 %, the highest associated with F. solani SC (67 %) and F. proliferatum (62.5 %). A wide range of antifungal susceptibilities was observed. Amphotericin B was the most potent antifungal in vitro, and itraconazole the least effective. The azoles exhibited lower minimum inhibitory concentrations (MICs) against F. verticillioides strains, with posaconazole having a slightly better performance, while F. solani SC isolates were resistant to all three azoles tested. The essential agreement between the Etest and the EUCAST method was 100 % for itraconazole and voriconazole, and 96 % for amphotericin B and posaconazole. In conclusion, we confirm that fusariosis is a rare but severe event in Europe, that G. fujikuroi SC is the predominant cause of deep infections and that different species have different antifungal in vitro susceptibility patterns.

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.

Taxonomy and epidemiology of Mucor irregularis, agent of chronic cutaneous mucormycosis.

Mucormycosis usually presents as a progressive infection with significant angio-invasion. Mucormycosis due to Mucor irregularis (formerly Rhizomucor variabilis var. variabilis), however, is exceptional in causing chronic cutaneous infection in immunocompetent humans, ultimately leading to severe morbidity if left untreated. More than 90 % of the cases known to date were reported from Asia, mainly from China. The nearest neighbour of M. irregularis is the saprobic species M. hiemalis. The aim of this study was to evaluate the taxonomic position, epidemiology, and intra- and inter-species diversity of M. irregularis based on 21 strains (clinical n = 17) by multilocus analysis using ITS, LSU, RPB1 and RPB2 genes, compared to results of cluster analysis with amplified fragment length polymorphism (AFLP) data. By combining MLST and AFLP analyses, M. irregularis was found to be monophyletic with high bootstrap support, and consisted of five subgroups, which were not concordant in all partitions. It was thus confirmed that M. irregularis is a single species at 96.1-100 % ITS similarity and low recombination rates between populations. Some geographic structuring was noted with some localised populations, which may be explained by limited air-dispersal. The natural habitat of the species is likely to be in soil and decomposing plant material.

Complement activation and formation of the membrane attack complex on serogroup B Neisseria meningitidis in the presence or absence of serum bactericidal activity.

Encapsulated meningococci are complement sensitive only in the presence of bactericidal antibodies by yet-unexplored mechanisms. The objective of this study was to investigate the involvement of major bacterial surface constituents on complement activation and membrane attack complex (MAC) formation on serogroup B meningococci in the presence or absence of antibody-dependent serum bactericidal activity (SBA). The strains used were the encapsulated H44/76, five of its variants differing in capsulation and expression of the class 1 porin (PorA), and its lipopolysaccharide (LPS)-deficient isogenic mutant (LPS(-)) pLAK33. Two normal sera, one with high SBA (SBA(+)) and one with no bactericidal activity (SBA(-)) against H44/76 as well as an a-gamma-globulinemic serum were used for sensibilization of the bacteria. C3b and iC3b deposition on H44/76, its unencapsulated variant v24, and pLAK33 was similar in SBA(+) and SBA(-) serum, and no difference was present between the strains. MAC deposition on H44/76 was higher in SBA(+) serum than in SBA(-) serum and the a-gamma-globulinemic serum. The amounts of C3b on H44/76, v24, and pLAK33 in the a-gamma-globulinemic serum were also not different, indicating immunoglobulin G (IgG)- and LPS-independent complement activation. H44/76 PorA(+) and its PorA(-) variant and the v24 PorA(+) and its PorA(-) variant incubated in SBA(-) serum induced comparable amounts of MAC, despite their different serum sensitivities. Complement formation on the surface of the bacteria occurred almost exclusively via the classical pathway, but the considerable amounts of Bb measured in the serum indicated alternative pathway activation in the fluid phase. We conclude that complement deposition on meningococci is, for the most part, independent of classical pathway IgG and is not influenced by the presence of PorA or LPS on the meningococcal surface. Addition of an anti-PorA chimeric antibody to the nonbactericidal normal serum, while promoting a dose-related bacterial lysis, did not influence the amounts of C3b, iC3b, and MAC formed on the bacterial surface. These findings support the hypothesis that proper MAC insertion rather than the quantity of MAC formed on the bacterial surface is of importance for efficient lysis of meningococci.

Development of antibodies against tetravalent meningococcal polysaccharides in revaccinated complement-deficient patients.

Individuals deficient in C3 or a late complement component are susceptible to recurrent meningococcal infections. Since they experience meningococcal episodes mostly with uncommon meningococcal serogroups, vaccination with a tetravalent vaccine containing A, C, Y and W135 polysaccharides has been suggested. We vaccinated a cohort of two C3 and 17 late complement component-deficient (LCCD) patients, revaccinated them 7 years later and investigated the development of their IgG antibodies to the capsular polysaccharides of the meningococcal vaccine. Seven years after the first vaccination levels of IgG antibodies declined compared with the levels present at 6 months after the first vaccination, but were still at least four times higher than before vaccination. Levels of antibodies to Y polysaccharide in serum of complement-deficient patients were rather low but they did not differ significantly from those in serum of healthy non-related controls (P = 0.07). Three months after the second vaccination IgG antibodies against all polysaccharides increased, exceeding those measured at 6 months after the first vaccination. In the 8 years of observation after the first vaccination two new meningococcal infections with strains related to the vaccine (serogroup Y strains) occurred in two patients, 3.5 and 5 years after the first vaccination. Our findings show that high IgG antibody levels against the tetravalent meningococcal polysaccharide vaccine were reached after revaccination of two C3 and 17 LCCD individuals 7 years after the first vaccination. Whether revaccination should be required within a period shorter than 7 years is discussed, since two vaccinees developed meningococcal disease to vaccine serogroup Y.

Protection against meningococcal serogroup ACYW disease in complement-deficient individuals vaccinated with the tetravalent meningococcal capsular polysaccharide vaccine.

Individuals with properdin, C3 or late complement component deficiency (LCCD) frequently develop meningococcal disease. Vaccination of these persons has been recommended, although reports on efficacy are scarce and not conclusive. We immunized 53 complement-deficient persons, of whom 19 had properdin deficiency, seven a C3 deficiency syndrome and 27 had LCCD with the tetravalent (ACYW) meningococcal capsular polysaccharide vaccine. Serological studies were performed in 43 of them. As controls 25 non-complement-deficient relatives of the complement-deficient vaccinees and 21 healthy non-related controls were vaccinated. Post-vaccination, complement-deficient individuals and controls developed a significant immunoglobulin-specific antibody response to capsular polysaccharides group A, C, Y, W135, but a great individual variation was noticed. Also, the proportion of vaccinees of the various vaccinated groups with a significant increase in bactericidal titre (assayed with heterologous complement) was similar. Opsonization of meningococci A and W135 with sera of the 20 LCCD individuals yielded in 11 (55%) and eight (40%) sera a significant increase of phagocytic activity after vaccination, respectively. Despite vaccination, four complement-deficient patients experienced six episodes of meningococcal disease in the 6 years post-vaccination. Four episodes were due to serogroup B, not included in the vaccine. Despite good response to serogroup Y upon vaccination, disease due to serogroup Y occurred in two C8beta-deficient patients, 3.5 and 5 years post-vaccination. These results support the recommendation to vaccinate complement-deficient individuals and to revaccinate them every 3 years.

The effect of mannan-binding lectin on opsonophagocytosis of Neisseria meningitidis.

Mannan-binding lectin (MBL), an acute phase protein with a structure and a function very similar to that of C1q, is known to act as an opsonin binding to a number of microorganisms. In order to investigate the effect of MBL on the phagocytic killing of meningococci, a serogroup B meningococcal strain (H44/76) and its unencapsulated variant v24, as well as a serogroup A meningococcal strain were opsonized with MBL (purified from normal human plasma at the State Serum Institute, Denmark) and used in a phagocytic killing assay at a density of 7 x 10(3) CFU/ml. Polymorphonuclear cells (PMNs) from one healthy donor were isolated by density gradient centrifugation over Percoll and added to the system (7 x 10(6) cells/ml). In a first set of experiments without addition of serum or complement, no influence of MBL was observed on the killing of any of these strains. Addition of MBL to non-opsonized bacteria of the serogroup A strain did not result in enhanced killing either; on the contrary, the growth of this strain increased significantly when a high MBL concentration (40 micrograms/ml) was used in the presence of PMNs. Further investigations were performed using sera of five individuals with late complement component deficiency (LCCD) and a concomitant MBL deficiency, vaccinated with a tetra-valent (ACYW135) meningococcal capsular polysaccharide vaccine. Pre- and post-vaccination sera (50% final concentration) were tested against a group A strain opsonized or not with MBL. In only one patient was there a moderate increase of killing of the opsonized bacteria after vaccination compared to pre-vaccination serum. Our results suggest that MBL may not play a significant role in the opsonophagocytosis of meningococci, irrespective of its binding to unencapsulated and serogroup A strains.