Charalampos Antachopoulos

Hippokration General Hospital, Athens, Athens, Attiki, Greece

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Publications (29)101.36 Total impact

  • Article: 30th ESPID Annual Meeting in Thessaloniki, Greece: Three Decades of ESPID.
    Emmanuel Roilides, Charalampos Antachopoulos
    The Pediatric Infectious Disease Journal 10/2012; 31(10):1078-9. · 3.58 Impact Factor
  • Article: Drug-resistant tuberculosis in two children in Greece: Report of the first extensively drug-resistant case.
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    ABSTRACT: Extensively drug-resistant (XDR) tuberculosis (TB) represents a serious and growing problem in both endemic and non-endemic countries. We describe a 2.5-year-old girl with XDR-pulmonary TB and an 18-month-old boy with pre-XDR-central nervous system TB. Patients received individualized treatment with second-line anti-TB agents based on genotypic and phenotypic drug susceptibility testing results. Both children achieved culture conversion 3 months and 1 month after treatment initiation, respectively. The child with XDR-pulmonary TB showed evidence of cure while treatment adverse events were managed without treatment interruption. The child with pre-XDR-central nervous system TB after 6-month hospitalization with multiple infectious complications had a dismal end due to hepatic insufficiency possibly related to anti-TB treatment. This is the first report of children with pre-XDR and XDR TB in Greece, emphasizing the public health dimensions and management complexity of XDR TB.
    European Journal of Pediatrics 08/2012; · 1.88 Impact Factor
  • Article: Immunotherapy against invasive mold infections.
    Charalampos Antachopoulos, Aspasia Katragkou, Emmanuel Roilides
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    ABSTRACT: Invasive infections due to filamentous fungi, such as Aspergillus spp., Zygomycetes, Scedosporium and Fusarium spp., cause significant morbidity and mortality in immunocompromised patients with hematological malignancies, recipients of hematopoietic stem cell transplants and those with chronic granulomatous disease. Despite antifungal therapy, the outcome is often unfavorable in these patients; immune restoration is considered as the cornerstone of successful treatment. Important aspects of human immune response against fungi include effective innate immune response expressed as effective phagocytic functions and a balance between proinflammatory and regulatory adaptive immune responses. A number of immunomodulatory approaches, including the administration of enhancing cytokines, adoptive transfer of pathogen-specific T lymphocytes and granulocyte transfusions have been investigated as adjunctive treatments against serious mold infections. Despite encouraging in vitro and in vivo data, current clinical evidence is not sufficient to allow firm recommendations on the use of these immunomodulatory modalities in serious mold infections.
    Immunotherapy 01/2012; 4(1):107-20. · 1.85 Impact Factor
  • Article: Ventriculitis caused by Aspergillus fumigatus in a child with central nervous system tuberculosis.
    Mycoses 09/2011; 54(5):e627-30. · 2.25 Impact Factor
  • Article: Activities of triazole-echinocandin combinations against Candida species in biofilms and as planktonic cells.
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    ABSTRACT: Biofilm formation complicates the treatment of various infections caused by Candida species. We investigated the effects of simultaneous or sequential combinations of two triazoles, voriconazole (VRC) and posaconazole (PSC), with two echinocandins, anidulafungin (AND) and caspofungin (CAS), against Candida albicans and Candida parapsilosis biofilms in comparison to their planktonic counterparts. Antifungal activity was assessed by the 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]2H-tetrazolium-5-carboxanilide (XTT) metabolic assay. Antifungal-agent interactions were analyzed by the Bliss independence model in the simultaneous-treatment studies and by analysis of variance (ANOVA) in the sequential-treatment studies. Against C. albicans planktonic cells, the simultaneous combination of PSC (32 to 128 mg/liter) and CAS (0.008 to 0.25 mg/liter) was synergistic; the combinations of PSC (128 to 1,024 mg/liter) with AND (0.03 to 0.5 mg/liter) and VRC (32 to 512 mg/liter) with AND (0.008 to 0.03 mg/liter) were antagonistic. Against C. parapsilosis planktonic cells, the interaction between VRC (32 to 1,024 mg/liter) and CAS (1 to 16 mg/liter) was antagonistic. All simultaneous antifungal combinations demonstrated indifferent interactions against biofilms of both Candida species. Damage to biofilms of both species increased (P<0.01) in the presence of subinhibitory concentrations of echinocandins (0.008 to 0.064 mg/liter), followed by the addition of PSC (512 mg/liter for C. albicans and 64 to 512 mg/liter for C. parapsilosis) or VRC (256 to 512 mg/liter for C. albicans and 512 mg/liter for C. parapsilosis). Triazole-echinocandin combinations do not appear to produce antagonistic effects against Candida sp. biofilms, while various significant interactions occur with their planktonic counterparts.
    Antimicrobial Agents and Chemotherapy 02/2011; 55(5):1968-74. · 4.84 Impact Factor
  • Article: Outcome of urinary tract infections caused by extended spectrum β-lactamase-producing Enterobacteriaceae in children.
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    ABSTRACT: The outcome of patients with urinary tract infections caused by extended spectrum β-lactamases (ESBL)-producing bacteria (cases) was compared with that of matched controls with urinary tract infections caused by non-extended spectrum β-lactamases-producing isolates. Significantly, more case patients received inappropriate empiric therapy than controls. Nevertheless, clinical and microbiologic outcomes as well as formation of renal scars did not differ between the 2 groups.
    The Pediatric Infectious Disease Journal 01/2011; 30(8):707-10. · 3.58 Impact Factor
  • Article: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) due to AIRET16M mutation in a consanguineous Greek girl.
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    ABSTRACT: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) or autoimmune polyendocrine syndrome type 1 (APS-1) is a rare autosomal recessive disease caused by mutations of the AutoImmune REgulator (AIRE) gene, an important mediator of tolerance to self-antigens. It is characterized by two out of three major components: chronic mucocutaneous candidiasis, hypoparathyroidism and Addison's disease. We present an 11-year-old girl suffering from recurrent episodes of mucocutaneous candidiasis and onychomycosis from 1 to 6 years of age, and transient alopecia at the age of 4 years. Hypoparathyroidism and dental enamel hypoplasia were diagnosed at 8 years. Autoantibodies to thyroid and adrenal glands were not detected and all other endocrine functions have remained normal. Genetic analysis revealed that the patient was homozygous for the mutation T16M in exon 1 of the AIRE gene (p.T16M, c.47C>T). This is the first APECED case reported for carrying this mutation in homozygous form. Parents were third cousins and heterozygous carriers of this mutation.
    Journal of pediatric endocrinology & metabolism: JPEM 01/2011; 24(7-8):599-601. · 0.88 Impact Factor
  • Article: Serum and cerebrospinal fluid levels of colistin in pediatric patients.
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    ABSTRACT: Using a liquid chromatography-tandem mass spectrometry method, the serum and cerebrospinal fluid (CSF) concentrations of colistin were determined in patients aged 1 months to 14 years receiving intravenous colistimethate sodium (60,000 to 225,000 IU/kg of body weight/day). Only in one of five courses studied (a 14-year-old receiving 225,000 IU/kg/day) did serum concentrations exceed the 2 microg/ml CLSI/EUCAST breakpoint defining susceptibility to colistin for Pseudomonas and Acinetobacter. CSF colistin concentrations were <0.2 microg/ml but increased in the presence of meningitis (approximately 0.5 microg/ml or 34 to 67% of serum levels).
    Antimicrobial Agents and Chemotherapy 09/2010; 54(9):3985-7. · 4.84 Impact Factor
  • Article: Colistin administration to pediatric and neonatal patients.
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    ABSTRACT: Emergence of multidrug-resistant Gram-negative nosocomial pathogens has led to resurgence of colistin use. Safety and efficacy data regarding colistin use in pediatric patients are sparse, while optimal dosage has not been defined. We present a case series of neonates and children without cystic fibrosis treated with various doses of colistin intravenously. The records of patients who received colistin in a tertiary-care hospital from January 2007 to March 2009 were reviewed. Thirteen patients (median age 5 years, range 22 days to 14 years) received 19 courses of colistin as treatment of pneumonia, central nervous system infection, bacteremia, or complicated soft tissue infection. The isolated pathogens were Acinetobacter baumannii, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Daily dose of colistin (colistimethate) ranged between 40,000 and 225,000 IU/kg. Duration of administration ranged from 1 to 133 days. Other antimicrobials were co-administered in 18/19 courses. Increase of serum creatinine in one patient was associated with co-administration of colistin and gentamicin. Sixteen of 19 courses had a favorable outcome, and only two of the three deaths were infection-related. Colistin intravenous administration appears well tolerated even at higher than previously recommended doses and of prolonged duration.
    European Journal of Pediatrics 07/2010; 169(7):867-74. · 1.88 Impact Factor
  • Article: A 5-year epidemiological study of nosocomial bloodstream infections in a neurosurgery department.
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    ABSTRACT: The characteristics of nosocomial bloodstream infections (BSIs) in a neurosurgical department were studied over a 5-year period. The rate of nosocomial BSI was 3.0%. Gram-negative bacteria were the most commonly isolated pathogens (65.9% of isolates). For all the pathogens isolated, the rate of resistance to commonly used antimicrobial agents was high. Of the 101 patients with nosocomial BSI, 50 (49.5%) died during their stay at the Department of Neurosurgery. At the same time, overall mortality rate among neurosurgical inpatients without nosocomial BSI was 5.4% (ie, 175 of 3,216 patients died).
    Infection Control and Hospital Epidemiology 02/2010; 31(4):414-7. · 3.67 Impact Factor
  • Source
    Article: Risk factors for nasopharyngeal carriage of drug-resistant Streptococcus pneumoniae: data from a nation-wide surveillance study in Greece.
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    ABSTRACT: A nation-wide surveillance study was conducted in Greece in order to provide a representative depiction of pneumococcal carriage in the pre-vaccination era and to evaluate potential risk factors for carriage of resistant strains in healthy preschool children attending daycare centers. A study group was organized with the responsibility to collect nasopharyngeal samples from children. Questionnaires provided demographic data, data on antibiotic consumption, family and household data, and medical history data. Pneumococcal isolates were tested for their susceptibility to various antimicrobial agents and resistant strains were serotyped. Between February and May 2004, from a total population of 2536 healthy children, a yield of 746 pneumococci was isolated (carriage rate 29.41%). Resistance rates differed among geographic regions. Recent antibiotic use in the last month was strongly associated with the isolation of resistant pneumococci to a single or multiple antibiotics. Serotypes 19F, 14, 9V, 23F and 6B formed 70.6% of the total number of resistant strains serotyped. Recent antibiotic use is a significant risk factor for the colonization of otherwise healthy children's nasopharynx by resistant strains of S pneumoniae. The heptavalent pneumococcal conjugate vaccine could provide coverage for a significant proportion of resistant strains in the Greek community. A combined strategy of vaccination and prudent antibiotic use could provide a means for combating pneumococcal resistance.
    BMC Infectious Diseases 08/2009; 9:120. · 3.12 Impact Factor
  • Article: Fungal biomass is a key factor affecting polymorphonuclear leucocyte-induced hyphal damage of filamentous fungi.
    Charalampos Antachopoulos, Joanne P Demchok, Emmanuel Roilides, Thomas J Walsh
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    ABSTRACT: Previous studies have not systematically assessed the effect of fungal biomass on polymorphonuclear leucocyte (PMN)-induced hyphal damage (HD) of filamentous fungi. We hypothesised that fungal biomass is a significant factor affecting PMN-induced HD. One isolate each consisting of a volume of 2 x 10(4) conidia ml(-1) of Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, Rhizopus oryzae, Rhizopus microsporus, Cunninghamella bertholletiae, Scedosporium prolificans and Fusarium solani were incubated for six different time periods yielding biomass values between 0.01 and 0.1 optical density (OD, 405 nm). Polymorphonuclear leucocyte were added at effector-target (E : T) ratios of 5 : 1, 10 : 1, 20 : 1, 50 : 1 and 100 : 1, and HD was assessed by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide] metabolic assay. Hyphal damage decreased with increasing biomass following the sigmoid (E(max)) model (median R(2): 0.87). Hyphal damage at 0.01 OD exceeded HD at 0.1 OD (P < 0.01) by >twofold in 64 out of 80 comparisons. The sigmoid curves were shifted to the right with higher E : T ratios; the EC(50) values (OD values showing HD halfway between maximal and minimal HD) obtained for 50 : 1 or 100 : 1 were higher than for 5 : 1 (P < 0.01). Using the same E : T ratio, interspecies differences were observed; for 5 : 1, lower EC(50) values were obtained for A. flavus and the zygomycete species. In conclusion, PMN-induced HD decreases with increasing biomass. This effect is both species-dependent and E : T ratio-dependent.
    Mycoses 07/2009; 53(4):321-8. · 2.25 Impact Factor
  • Article: Differential correlation between rates of antimicrobial drug consumption and prevalence of antimicrobial resistance in a tertiary care hospital in Greece.
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    ABSTRACT: To investigate whether there is a correlation between the rates of antimicrobial drug consumption in hospital departments and the prevalence of antimicrobial resistance among clinically important bacteria recovered in the hospital. Retrospective study. Tertiary care hospital in Greece. Data on antimicrobial consumption (from January 2001 through December 2004) were expressed as defined daily doses per 100 bed-days. The prevalence of antimicrobial resistance among isolates of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterococcus faecium recovered during the same time period were calculated by the microbiology department. We then performed the following analyses: (1) a comparison of the consumption rates for different antimicrobial groups in individual hospital departments, (2) a comparison of the prevalence of resistance to different antimicrobials, and (3) a correlation analysis of antimicrobial consumption rates and the prevalence of antimicrobial resistance. The rates of antimicrobial consumption and the prevalence of resistance varied substantially among the hospital's departments. The annual rate of consumption for carbapenems correlated with the rate of consumption for glycopeptides and third-generation cephalosporins (P < .05). Among P. aeruginosa isolates, the prevalence of imipenem resistance correlated with the prevalence of resistance to amikacin, ciprofloxacin, and ceftazidime (P < .05). The rate of carbapenem consumption correlated with the prevalence of imipenem resistance among P. aeruginosa and A. baumannii isolates (P < .05). The rate of aminoglycoside consumption correlated with the prevalence of amikacin resistance among P. aeruginosa, K. pneumoniae, and E. coli isolates (P < .05). However, the rate of consumption for fluoroquinolones and glycopeptides had no correlation with the prevalence of ciprofloxacin resistance among gram-negative bacteria or vancomycin resistance among E. faecium isolates. These data are suggestive of a differential relationship between antimicrobial consumption and the prevalence of antimicrobial resistance among various species and for various antimicrobial agents. These findings may help to optimize antimicrobial prescription policies in the hospital, especially in departments that have both high rates of antimicrobial consumption and a high prevalence of antimicrobial resistance.
    Infection Control and Hospital Epidemiology 07/2008; 29(7):615-22. · 3.67 Impact Factor
  • Article: Infections caused by Scedosporium spp.
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    ABSTRACT: Scedosporium spp. are increasingly recognized as causes of resistant life-threatening infections in immunocompromised patients. Scedosporium spp. also cause a wide spectrum of conditions, including mycetoma, saprobic involvement and colonization of the airways, sinopulmonary infections, extrapulmonary localized infections, and disseminated infections. Invasive scedosporium infections are also associated with central nervous infection following near-drowning accidents. The most common sites of infection are the lungs, sinuses, bones, joints, eyes, and brain. Scedosporium apiospermum and Scedosporium prolificans are the two principal medically important species of this genus. Pseudallescheria boydii, the teleomorph of S. apiospermum, is recognized by the presence of cleistothecia. Recent advances in molecular taxonomy have advanced the understanding of the genus Scedosporium and have demonstrated a wider range of species than heretofore recognized. Studies of the pathogenesis of and immune response to Scedosporium spp. underscore the importance of innate host defenses in protection against these organisms. Microbiological diagnosis of Scedosporium spp. currently depends upon culture and morphological characterization. Molecular tools for clinical microbiological detection of Scedosporium spp. are currently investigational. Infections caused by S. apiospermum and P. boydii in patients and animals may respond to antifungal triazoles. By comparison, infections caused by S. prolificans seldom respond to medical therapy alone. Surgery and reversal of immunosuppression may be the only effective therapeutic options for infections caused by S. prolificans.
    Clinical microbiology reviews 02/2008; 21(1):157-97. · 14.69 Impact Factor
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    Article: Comparative in vitro pharmacodynamics of caspofungin, micafungin, and anidulafungin against germinated and nongerminated Aspergillus conidia.
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    ABSTRACT: The concentration-dependent effects of echinocandins on the metabolic activity of Aspergillus spp. were comparatively studied by using nongerminated and germinated conidia. The susceptibilities of 11 Aspergillus fumigatus, 8 A. terreus and 8 A. flavus isolates to caspofungin, micafungin, and anidulafungin were studied by a CLSI (formerly NCCLS) M38-A broth microdilution-based method. After 48 h of incubation the minimum effective concentration (MEC) was defined microscopically. Metabolic activity was assessed by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay and modeled by using the sigmoid (E max) or "bell-shaped" model. The median MEC values of caspofungin (0.5 to 1 microg/ml), micafungin (0.06 to 0.12 microg/ml), and anidulafungin (0.03 microg/ml) against nongerminated conidia increased by 0 to 1, 1 to 2, and 2 to 3 twofold dilutions, respectively (depending on the species), over those against germinated conidia. A similar shift to the right was demonstrated for the corresponding curves of metabolic activity. There was a significant correlation between the degrees of maximal metabolic inhibition caused by different echinocandins at both the species level (greater inhibition for A. flavus) and the strain level (r = 0.84 to 0.93; P < 0.0001). Paradoxical increases in metabolism in the presence of higher concentrations of caspofungin, micafungin, and anidulafungin were detected in 6, 2, and 5 of the A. fumigatus isolates, respectively; 5, 1, and 2 of the A. terreus isolates, respectively; and 1, 0, and 0 of the A. flavus isolates, respectively. Based on the model, 50% of the maximal paradoxical increase was detected with 4.2, 11.1, and 10.8 microg/ml of caspofungin, micafungin, and anidulafungin, respectively. All echinocandins therefore exerted comparable levels of maximal metabolic inhibition against Aspergillus spp. at concentrations that were differentially increased for germinated versus nongerminated conidia. The paradoxical increase in metabolism occurred more frequently and at lower concentrations with caspofungin than with micafungin and anidulafungin.
    Antimicrobial Agents and Chemotherapy 01/2008; 52(1):321-8. · 4.84 Impact Factor
  • Chapter: Zygomycosis (Mucormycosis)
    Charalampos Antachopoulos, Juan C. Gea-Banacloche, Thomas J. Walsh
    12/2007: pages 227-243;
  • Article: Fungal infections in primary immunodeficiencies.
    Charalampos Antachopoulos, Thomas J Walsh, Emmanuel Roilides
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    ABSTRACT: Patients with phagocytic, cellular, combined and other primary immunodeficiencies exhibit immune deficits that confer increased susceptibility to fungal infections. A number of yeasts and moulds, most commonly Candida and Aspergillus but also Cryptococcus, Histoplasma, Paecilomyces, Scedosporium, Trichosporon, Penicillium and other, rarely isolated, fungal organisms, have been variably implicated in causing disease in patients with chronic granulomatous disease, severe combined immunodeficiency, chronic mucocutaneous candidiasis, hyper-IgE syndrome, myeloperoxidase deficiency, leukocyte adhesion deficiency, defects in the interferon-gamma/interleukin-12 axis, DiGeorge syndrome, X-linked hyper-IgM syndrome, Wiskott-Aldrich syndrome and common variable immunodeficiency. Differences in the spectrum of fungal pathogens as well as in the incidence and clinical presentation of the infections may be observed among patients, depending upon different immune disorders. Fungal infections in these individuals may occasionally be the presenting clinical manifestation of a primary immunodeficiency and can cause significant morbidity and potentially fatal outcome if misdiagnosed or mistreated. A high degree of suspicion is needed and establishment of diagnosis should actively be pursued using appropriate imaging, mycological and histological studies. A number of antifungal agents introduced over the last fifteen years, such as the lipid formulations of amphotericin B, the second-generation triazoles, and the echinocandins, increase the options for medical management of these infections. Surgery may also be needed in some cases, while the role of adjunctive immunotherapy has not been systematically evaluated. The low incidence of primary immunodeficiencies in the general population complicates single-center prospective or retrospective clinical studies aiming to address diagnostic or therapeutic issues pertaining to fungal infections in these patients.
    European Journal of Pediatrics 12/2007; 166(11):1099-117. · 1.88 Impact Factor
  • Article: Differential fungicidal activities of amphotericin B and voriconazole against Aspergillus species determined by microbroth methodology.
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    ABSTRACT: Antifungal agents may differ in their fungicidal activities against Aspergillus spp. In order to compare the fungicidal activities of voriconazole and amphotericin B against 40 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, we developed a new microbroth colorimetric method for assessing fungicidal activities and determining minimal fungicidal concentrations (MFCs). This methodology follows the antifungal susceptibility testing reference method M-38A for MIC determination. After drug removal and addition of fresh medium, growth of viable conidia adhering to the bottoms of the microtitration wells was assessed by a colorimetric assay of metabolic activity after 24 h of incubation. The new method was faster (six times), reproducible (92 to 97%), and in agreement with culture-based MFCs (91 to 100%). Differential fungicidal activities of voriconazole and amphotericin B were found among the three Aspergillus species, with A. fumigatus and A. flavus having the lowest (1 and 2 mg/liter, respectively) and A. terreus the highest (>16 mg/liter) median amphotericin B MFCs; A. flavus had a lower median voriconazole MFC (4 mg/liter) than the other species (>8 mg/liter; P < 0.05). Amphotericin B was fungicidal (MFC/MIC </= 4) against all A. fumigatus and A. flavus isolates but no A. terreus isolates, whereas voriconazole was fungicidal against 82% of A. flavus isolates and fungistatic (MFC/MIC > 4) against 94% of A. fumigatus and 84% of A. terreus isolates. The new methodology revealed a concentration-dependent sigmoid pattern of fungicidal effects, indicating that fungicidal activity is not an all-or-nothing phenomenon and that some degree of fungicidal action can be found even for agents considered fungistatic based on the MFC/MIC ratio.
    Antimicrobial Agents and Chemotherapy 10/2007; 51(9):3329-37. · 4.84 Impact Factor
  • Article: Concentration-dependent effects of caspofungin on the metabolic activity of Aspergillus species.
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    ABSTRACT: The minimum effective concentration (MEC) used to assess the in vitro antifungal activity of caspofungin against Aspergillus spp. is a qualitative endpoint requiring microscopic examination of hyphae. We therefore developed a tool for the quantitative assessment of caspofungin activity against Aspergillus spp. at clinically applicable concentrations. Susceptibility to caspofungin (0.008 to 8 microg/ml) was studied for 9 A. fumigatus, 8 A. flavus, and 12 A. terreus isolates based on the Clinical and Laboratory Standards Institute M38-A protocol. After 48 h of incubation, the MEC was defined microscopically, and metabolic activity assessed with a modified XTT assay, using 100 microg of the tetrazolium salt XTT/ml and 6.25 muM menadione. A significant reduction in metabolic activity was demonstrated at the MEC (0.25 to 0.5 microg/ml) for all Aspergillus spp. and was more pronounced for A. flavus (median metabolic activity, 25% of control) compared to A. fumigatus and A. terreus (median metabolism, 42 and 53%, respectively), allowing determination of MEC with the XTT assay (93 to 100% agreement with microscopic MEC). Fungal metabolism tended to reach the lowest levels (median, 17 to 38% of control) one to two dilutions higher than the MEC, at the minimum metabolic activity concentration (MMC). For 5 of 9 A. fumigatus isolates, 6 of 12 A. terreus isolates, and 1 of 8 A. flavus isolates, a paradoxical increase in metabolism was observed at concentrations greater than the MMC. Sigmoid (E(max)) or bell-shaped models described accurately (median R(2) = 0.97) the concentration-dependent metabolic changes in the absence or presence, respectively, of paradoxical response. Assessment of metabolic activity may provide useful quantitative endpoints for in vitro studies of caspofungin against Aspergillus spp.
    Antimicrobial Agents and Chemotherapy 04/2007; 51(3):881-7. · 4.84 Impact Factor
  • Article: Use of high inoculum for early metabolic signalling and rapid susceptibility testing of Aspergillus species.
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    ABSTRACT: To develop and evaluate a new method for rapid susceptibility testing of Aspergillus spp. based on early metabolic signalling of high-inoculum biomass. Susceptibility to amphotericin B and voriconazole was studied in 39 clinical isolates of Aspergillus spp. (16 Aspergillus fumigatus, 11 Aspergillus flavus, 12 Aspergillus terreus). At 6 or 8 h after inoculation for A. fumigatus and A. flavus, and at 8 or 12 h after inoculation for A. terreus, 100 microg/mL of the tetrazolium salt XTT and 25 microM menadione were added and absorbance measured at 450 nm after 2 h of incubation at 37 degrees C. Inocula used were 10(6) conidia/mL for A. fumigatus and A. terreus and 10(5) conidia/mL for A. flavus, as lower inocula exhibited very low metabolic activity at these time points. Data were analysed with the sigmoid E(max) model and compared with visual (lowest drug concentration showing no growth) and spectrophotometric MIC determination at 48 h (CLSI M38-A method). The E(max) model described well the concentration-effect relationship for early metabolic activity and 48 h fungal biomass (median r(2): 0.97 and 0.93, respectively). Use of the model allowed characterization and quantification of species- and drug-related differences in pharmacological inhibition of early metabolic activity as well as calculation of appropriate cutoff levels for MIC determination with the XTT assay. Using these cutoff levels, for A. fumigatus and A. flavus at both time points (6 and 8 h) and for A. terreus at 12 h, the agreement (+/- one dilution) of the XTT assay with the CLSI method was 91-100% and its reproducibility was 97-100%. This newly developed high-inoculum-based method provides rapid and reproducible MIC determinations for Aspergillus spp.
    Journal of Antimicrobial Chemotherapy 03/2007; 59(2):230-7. · 5.07 Impact Factor

Institutions

  • 2008–2012
    • Hippokration General Hospital, Athens
      Athens, Attiki, Greece
  • 2005–2011
    • Aristotle University of Thessaloniki
      • Faculty of Medicine
      Thessaloníki, Kentriki Makedonia, Greece
  • 2005–2009
    • National Cancer Institute (USA)
      • Pediatric Oncology Branch
      Bethesda, MD, USA
  • 2002
    • Aghia Sophia Children’s Hospital
      Athens, Attiki, Greece
    • Harokopion University of Athens
      Athens, Attiki, Greece