scholarly journals Comparison of clinical and biological characteristics of HIV-infected patients presenting Cryptococcus neoformans versus C. curvatus/C. laurentii meningitis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Bive Zono ◽  
Michel Moutschen ◽  
Hippolyte Situakibanza ◽  
Rosalie Sacheli ◽  
Gaultier Muendele ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Antifungal Susceptibility ◽  
Outcome Variable ◽  
Fisher Exact Test ◽  
Its Sequencing ◽  
Exact Test ◽  
India Ink

Abstract Background Cryptococcal meningitis is mainly caused by Cryptococcus neoformans/C. gattii complex. We compared the clinical, biological, and antifungal susceptibility profiles of isolates from HIV-Infected Patients (HIVIP) with C. neoformans (Cn) versus C. curvatus/C. laurentii (Cc/Cl) meningitis. Methods Comparative analytical study were conducted. Apart from patients’ clinical data, the following analysis were performed and the results were compared in both groups: biochemical examination, cryptococcal antigen test, India ink staining, and culture on Cerebral Spinal Fluid (CSF), strains identification by mass spectrometry, ITS sequencing, PCR serotyping and antifungal susceptibility. The main outcome variable was the “species of Cryptococcus identified”, which was compared to other variables of the same type using the Pearson Chi-square test or the Fisher exact test. Results A total of 23 (79.3%) Cn meningitis cases versus 6 (20.7%) Cc/Cl meningitis were retained.Cn meningitis was more frequently associated with headache (100% vs 50%, p = 0.005) than Cc/Cl meningitis and meningeal signs were more frequent in Cn infected patients. Biologically, hypoglycorrhachia and low CD4 count were more observed in Cn group (90% vs 20% of patients, p = 0.01; 45.6 vs 129.8 cells/µL, p = 0.02, respectively). A higher proportion of Cn strains (91.3%) showed a low Minimum Inhibitory Concentration (MIC) (< 8 mg/L) for fluconazole compared to Cc/Cl strains (66.7%). Also, Cc/Cl strains resistant to 5-flucytosine and amphotericin B were found in 16.7% of cases for each of the two antifungal agents. Cryptococcus detection by routine analysis (India ink, culture, and antigens) was better for Cn samples than Cc/Cl. Except ITS sequencing, which identified all strains of both groups, mass spectrometry and serotyping PCR identified Cn strains better than Cc/Cl (100% vs 80%, p = 0.1; 100% vs 0%, p < 0.0001, respectively). After treatment with amphotericin B, 5-flucytosine, and fluconazole in both groups, the outcome was similar. Conclusions Clinical presentation of Cn meningitis is certainly more severe than that of Cc/Cl meningitis, but Cc/Cl infection should be considered in the management of HIVIP with meningeal syndrome because of the diagnostic difficulty and the high MICs of antifungal agents required for the treatment of meningitis due to these cryptococcal species.

scholarly journals Trends in Antifungal Drug Susceptibility of Cryptococcus neoformans Isolates Obtained through Population-Based Surveillance in South Africa in 2002-2003 and 2007-2008

2011 ◽  
Vol 55 (6) ◽  
pp. 2606-2611 ◽  
Author(s):  
Nelesh P. Govender ◽  
Jaymati Patel ◽  
Marelize van Wyk ◽  
Tom M. Chiller ◽  
Shawn R. Lockhart ◽  
...  
Keyword(s):  
South Africa ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Drug Susceptibility ◽  
Population Based ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTCryptococcus neoformansis the most common cause of meningitis among adult South Africans with HIV infection/AIDS. Widespread use of fluconazole for treatment of cryptococcal meningitis and other HIV-associated opportunistic fungal infections in South Africa may lead to the emergence of isolates with reduced fluconazole susceptibility. MIC testing using a reference broth microdilution method was used to determine if isolates with reduced susceptibility to fluconazole or amphotericin B had emerged among cases of incident disease. Incident isolates were tested from two surveillance periods (2002-2003 and 2007-2008) when population-based surveillance was conducted in Gauteng Province, South Africa. These isolates were also tested for susceptibility to flucytosine, itraconazole, voriconazole, and posaconazole. Serially collected isolate pairs from cases at several large South African hospitals were also tested for susceptibility to fluconazole. Of the 487 incident isolates tested, only 3 (0.6%) demonstrated a fluconazole MIC of ≥16 μg/ml; all of these isolates were from 2002-2003. All incident isolates were inhibited by very low concentrations of amphotericin B and exhibited very low MICs to voriconazole and posaconazole. Of 67 cases with serially collected isolate pairs, only 1 case was detected where the isolate collected more than 30 days later had a fluconazole MIC value significantly higher than the MIC of the corresponding incident isolate. Although routine antifungal susceptibility testing of incident isolates is not currently recommended in clinical settings, it is still clearly important for public health to periodically monitor for the emergence of resistance.

scholarly journals Distribution and antifungal susceptibility of Candida species in patients with increased risk for fungal infections

2016 ◽  
Vol 62 (1) ◽  
pp. 65-76
Author(s):  
Gordana Mirchevska ◽  
Maja Jurhar Pavlova ◽  
Elena Trajkovska-Dokic ◽  
Zaklina Cekovska ◽  
Gordana Jankoska ◽  
...  
Keyword(s):  
Blood Culture ◽  
Amphotericin B ◽  
Critically Ill Patients ◽  
Candida Species ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Clinical Specimens ◽  
Fourth Group ◽  
Increased Risk

Candida species are opportunistic yeasts that can be a serious threat for immunocompromised and critically ill patients, and a cause for increased morbidity and mortality in hospitalized patients. The aim of this study was to determine the frequency and distribution of different Candida species in clinical specimens in patients with increased risk for fungal infections, and to determine the antifungal susceptibility profile of invasive Candida species to antifungal agents. During a two year period, clinical specimens from 120 patients divided into 4 groups were analysed at the Institute of microbiology and parasitology, Faculty of Medicine, Skopje, Republic of Macedonia. Each of these 4 groups consisted of specimens from 30 patients, with primary immune deficiency, critically ill patients treated in the intensive care units (ICU), patients with mucosal candidiasis only, and patients with cystic fibrosis. All specimens were investigated with conventional mycological methods. Identification of Candida species was performed with VITEK-2 system (bioMérieux, France). E-test strips of fluconazole, voriconazole, amphotericin B and caspofungin (AB bioMerieux, France) were used for determination of the antifungal susceptibility profile. In this study, a total of 115 isolates of Candida species were confirmed in different clinical specimens (91 isolates from mucosal surfaces and 24 isolates from blood culture). Colonisation of mucosal membranes of gastrointestinal, respiratory and/or urinary tracts was registered in 56.67% (17/30), 56.67% (17/30), 90% (27/30) and 100% (30/30) of the specimens in the first, second, third and fourth group respectively. In all four groups of patients, the following Candida species were confirmed: C. albicans - 55%, C. glabrata - 17.6%, C. parapsilosis - 7.7%, C. tropicalis - 6.6%, unidentified Candida species - 4.4%, C. dubliniensis - 3.3%, C. kefyr - 2.2%, and one isolate of C. rugosa, C. pelliculosa and C. krusei each. Positive blood culture was registered in 23.33% specimens from the first group, 43.33% in the second group, 23.08% of the third group, and in one specimen of the fourth group. The most frequent isolates from blood culture were C. tropicalis and C. krusei, followed by C. albicans, C. parapsilosis and C. tropicalis, and in the second group C. albicans and C. pelliculosa were equally distributed, followed by C. parapsilosis and C. glabrata. All invasive isolates of Candida species were susceptible to amphotericin B, voriconazole and caspofungin. Resistance to fluconazole was registered in 8.3% (2/24) of all confirmed Candida species. Dose-dependent susceptibility to fluconazole was confirmed in 46% (11/24) of the isolates. Our study confirms high prevalence of colonisation and candidemia with non-albicans Candida species. Resistance to antifungal agents was registered only in two isolates of C. krusei. An epidemiological study is necessary for surveillance of dynamics of candidemia and antifungal susceptibility profile of invasive isolates of Candida species in our patients.

scholarly journals Comparison of the Sensititre YeastOne and CLSI M38-A2 Microdilution Methods in Determining the Activity of Amphotericin B, Itraconazole, Voriconazole, and Posaconazole against Aspergillus Species

2018 ◽  
Vol 56 (10) ◽  
Author(s):  
Hsuan-Chen Wang ◽  
Ming-I Hsieh ◽  
Pui-Ching Choi ◽  
Chi-Jung Wu
Keyword(s):  
Aspergillus Fumigatus ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Aspergillus Species ◽  
Broth Microdilution ◽  
Content Type

ABSTRACT This study compared the YeastOne and reference CLSI M38-A2 broth microdilution methods for antifungal susceptibility testing of Aspergillus species. The MICs of antifungal agents were determined for 100 Aspergillus isolates, including 54 Aspergillus fumigatus (24 TR34/L98H isolates), 23 A. flavus, 13 A. terreus, and 10 A. niger isolates. The overall agreement (within 2 2-fold dilutions) between the two methods was 100%, 95%, 92%, and 90% for voriconazole, posaconazole, itraconazole, and amphotericin B, respectively. The voriconazole geometric mean (GM) MICs were nearly identical for all isolates using both methods, whereas the itraconazole and posaconazole GM MICs obtained using the YeastOne method were approximately 1 dilution lower than those obtained using the reference method. In contrast, the amphotericin B GM MIC obtained using the YeastOne method was 3.3-fold higher than that observed using the reference method. For the 24 A. fumigatus TR34/L98H isolates assayed, the categorical agreement (classified according to the CLSI epidemiological cutoff values) was 100%, 87.5%, and 83.3% for itraconazole, voriconazole, and posaconazole, respectively. For four A. niger isolates, the itraconazole MICs were >8 μg/ml using the M38-A2 method due to trailing growth, whereas the corresponding itraconazole MICs obtained using the YeastOne method were all ≤0.25 μg/ml without trailing growth. These data suggest that the YeastOne method can be used as an alternative for azole susceptibility testing of Aspergillus species and for detecting the A. fumigatus TR34/L98H isolates but that this method fails to detect A. niger isolates exhibiting trailing growth with itraconazole. Additionally, for isolates with azole MICs that approach or that are at susceptibility breakpoints or with high amphotericin B MICs detected using the YeastOne method, further MIC confirmation using the reference CLSI method is needed.

scholarly journals Susceptibility Patterns and Molecular Identification of Trichosporon Species

2005 ◽  
Vol 49 (10) ◽  
pp. 4026-4034 ◽  
Author(s):  
Juan L. Rodriguez-Tudela ◽  
Teresa M. Diaz-Guerra ◽  
Emilia Mellado ◽  
Virginia Cano ◽  
Cecilia Tapia ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Intergenic Spacer ◽  
Clinical Isolates ◽  
Rrna Genes ◽  
Correct Identification ◽  
Its Sequencing ◽  
Trichosporon Species

ABSTRACT The physiological patterns, the sequence polymorphisms of the internal transcriber spacer (ITS), and intergenic spacer regions (IGS) of the rRNA genes and the antifungal susceptibility profile were evaluated for their ability to identify Trichosporon spp. and their specificity for the identification of 49 clinical isolates of Trichosporon spp. Morphological and biochemical methodologies were unable to differentiate among the Trichosporon species. ITS sequencing was also unable to differentiate several species. However, IGS1 sequencing unambiguously identified all Trichosporon isolates. Following the results of DNA-based identification, Trichosporon asahii was the species most frequently isolated from deep sites (15 of 25 strains; 60%). In the main, other Trichosporon species were recovered from cutaneous samples. The majority of T. asahii, T. faecale, and T. coremiiforme clinical isolates exhibited resistance in vitro to amphotericin B, with geometric mean (GM) MICs >4 μg/ml. The other species of Trichosporon did not show high MICs of amphotericin B, and GM MICs were <1 μg/ml. Azole agents were active in vitro against the majority of clinical strains. The most potent compound in vitro was voriconazole, with a GM MIC ≤0.14 μg/ml. The sequencing of IGS correctly identified Trichosporon isolates; however, this technique is not available in many clinical laboratories, and strains should be dispatched to reference centers where these complex methods are available. Therefore, it seems to be more practical to perform antifungal susceptibility testing of all isolates belonging to Trichosporon spp., since correct identification could take several weeks, delaying the indication of an antifungal agent which exhibits activity against the infectious strain.

Management of Candidiasis in Critically Ill Patients

2002 ◽  
Vol 15 (2) ◽  
pp. 106-113
Author(s):  
Manjunath P. Pai ◽  
Larry H. Danziger ◽  
Susan L. Pendland
Keyword(s):  
Amphotericin B ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Economic Consequences ◽  
Drug Selection ◽  
Testing Method ◽  
Candida Infections

Fungal infections have been increasing at an alarming rate in critically ill patients. Candida is now the fourth most common pathogen isolated from the bloodstream and is associated with significant morbidity, mortality, and economic consequences. Novel antifungals have been developed in recent years to provide alternatives to amphotericin B, which continues to be the standard therapy for most invasive fungal infections. These alternatives include lipid-based amphotericin B, ketoconazole, fluconazole, itraconazole, caspofungin, and potentially voriconazole. Optimal therapy for the various forms of candidiasis remains controversial. A standardized antifungal susceptibility testing method for Candida isolates has been developed to assist drug selection, but its clinical relevance remains to be determined. The relative susceptibility of Candida isolates can be estimated by the species. Specifically, C krusei is resistant to azoles, C glabrata may be resistant to azoles, and C lusitaniae may be resistant to amphotericin B Candida infections can affect any organ system, and the diagnosis of such infections remains difficult. The Infectious Diseases Society of America recently developed guidelines for the management of candidiasis. This review includes a brief discussion of systemically administered antifungal agents and provides a synopsis of the practice guidelines for the management of candidiasis.

scholarly journals Postantifungal Effects of Echinocandin, Azole, and Polyene Antifungal Agents against Candida albicans andCryptococcus neoformans

2000 ◽  
Vol 44 (4) ◽  
pp. 1108-1111 ◽  
Author(s):  
Erika J. Ernst ◽  
Michael E. Klepser ◽  
Michael A. Pfaller
Keyword(s):  
Candida Albicans ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Postantifungal Effect

ABSTRACT The postantifungal effect (PAFE) of fluconazole, MK-0991, LY303366, and amphotericin B was determined against isolates of Candida albicans and Cryptococcus neoformans. Concentrations ranging from 0.125 to 4 times the MIC were tested following exposure to the antifungal for 0.25 to 1 h. Combinations of azole and echinocandin antifungals (MK-0991 and LY303366) were tested againstC. neoformans. Fluconazole displayed no measurable PAFE against Candida albicans or Cryptococcus neoformans, either alone or in combination with either echinocandin antifungal. MK-0991, LY303366, and amphotericin B displayed a prolonged PAFE of greater than 12 h againstCandida spp. when tested at concentrations above the MIC for the organism and 0 to 2 h when tested at concentrations below the MIC for the organism.

scholarly journals Antifungal Susceptibility Profile of Human-Pathogenic Species of Lichtheimia

2010 ◽  
Vol 54 (7) ◽  
pp. 3058-3060 ◽  
Author(s):  
Ana Alastruey-Izquierdo ◽  
Isabel Cuesta ◽  
Grit Walther ◽  
Manuel Cuenca-Estrella ◽  
Juan Luis Rodriguez-Tudela
Keyword(s):  
Combination Therapy ◽  
Amphotericin B ◽  
Potential Role ◽  
Antifungal Agents ◽  
Active Drug ◽  
Antifungal Susceptibility ◽  
Pathogenic Species

ABSTRACT Forty-four isolates belonging to human pathogenic species of Lichtheimia were tested against nine antifungal agents by using the EUCAST methodology. No remarkable differences were found between the clinical species, although L. ramosa showed slightly higher MICs for all drugs. Amphotericin B was the most active drug. Among azole drugs, posaconazole had the best activity in vitro and voriconazole was inactive. Echinocandins showed activity for some isolates, suggesting a potential role in combination therapy.

scholarly journals Nitrogen concentration affects amphotericin B and fluconazole tolerance of pathogenic cryptococci

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Caylin Bosch ◽  
Barbra Toplis ◽  
Jo-Marie Vreulink ◽  
Heinrich Volschenk ◽  
Alfred Botha
Keyword(s):  
Environmental Stress ◽  
Amphotericin B ◽  
Natural Habitat ◽  
Nitrogen Concentration ◽  
Antifungal Susceptibility ◽  
Drug Tolerance ◽  
Ergosterol Biosynthesis ◽  
Variable Effect ◽  
India Ink ◽  
Nitrogen Concentrations

ABSTRACT Environmental stress often causes phenotypic changes among pathogenic cryptococci, such as altered antifungal susceptibility, changes in capsule and melanin formation, as well as altered levels of the membrane sterol and antifungal target, ergosterol. We therefore hypothesised that nitrogen limitation, a prevalent environmental stress in the natural habitat of these yeasts, might affect virulence and antifungal susceptibility. We tested the effect of different nitrogen concentrations on capsule, melanin and ergosterol biosynthesis, as well as amphotericin B (AmB) and fluconazole (FLU) susceptibility. This was achieved by culturing cryptococcal strains representing Cryptococcus neoformans and Cryptococcus gattii in media with high (0.53 g/l), control (0.42 g/l) and low (0.21 g/l) NH4Cl concentrations. India ink staining was used to determine capsule thickness microscopically, while melanin and ergosterol content were determined spectrophotometrically. We found that lower nitrogen concentrations enhanced both ergosterol and capsule biosynthesis, while a variable effect was observed on melanisation. Evaluation of drug tolerance using time-kill methodology, as well as tests for FLU heteroresistance, revealed that the low nitrogen cultures had the highest survival percentages in the presence of both AmB and FLU, and showed the highest frequency of FLU heteroresistance, suggesting that nitrogen concentration may indeed influence drug tolerance.

scholarly journals Trends in Antifungal Drug Susceptibility of Cryptococcus neoformans Isolates in the United States: 1992 to 1994 and 1996 to 1998

2001 ◽  
Vol 45 (11) ◽  
pp. 3065-3069 ◽  
Author(s):  
Mary E. Brandt ◽  
Michael A. Pfaller ◽  
Rana A. Hajjeh ◽  
Richard J. Hamill ◽  
Peter G. Pappas ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Clinical Laboratory ◽  
The United States ◽  
Drug Susceptibility ◽  
Antifungal Drug ◽  
National Committee ◽  
Broth Microdilution Method

ABSTRACT The antifungal drug susceptibilities of two collections ofCryptococcus neoformans isolates obtained through active laboratory-based surveillance from 1992 to 1994 (368 isolates) and 1996 to 1998 (364 isolates) were determined. The MICs of fluconazole, itraconazole, and flucytosine were determined by the National Committee for Clinical Laboratory Standards broth microdilution method; amphotericin B MICs were determined by the E-test. Our results showed that the MIC ranges, the MICs at which 50% of isolates are inhibited (MIC50s), and the MIC90s of these four antifungal agents did not change from 1992 to 1998. In addition, very small numbers of isolates showed elevated MICs suggestive of in vitro resistance. The MICs of amphotericin B were elevated (≥2 μg/ml) for 2 isolates, and the MICs of flucytosine were elevated (≥32 μg/ml) for 14 isolates. Among the azoles, the fluconazole MIC was elevated (≥64 μg/ml) for 8 isolates and the itraconazole MIC (≥1 μg/ml) was elevated for 45 isolates. Analysis of 172 serial isolates from 71 patients showed little change in the fluconazole MIC over time. For isolates from 58 patients (82% of serial cases) there was either no change or a twofold change in the fluconazole MIC. In contrast, for isolates from seven patients (12% of serial cases) the increase in the MIC was at least fourfold. For isolates from another patient there was a 32-fold decrease in the fluconazole MIC over a 1-month period. We conclude that in vitro resistance to antifungal agents remains uncommon in C. neoformans and has not significantly changed with time during the past decade.

scholarly journals Susceptibility of Cryptococcus neoformans Biofilms to Antifungal Agents In Vitro

2006 ◽  
Vol 50 (3) ◽  
pp. 1021-1033 ◽  
Author(s):  
Luis R. Martinez ◽  
Arturo Casadevall
Keyword(s):  
Confocal Microscopy ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Biofilm Formation ◽  
Antifungal Agents ◽  
Capsular Polysaccharide ◽  
Antifungal Drugs ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sequence Of Events ◽  
Biofilm Development

ABSTRACT Microbial biofilms contribute to virulence and resistance to antibiotics by shielding microbial cells from host defenses and antimicrobial drugs, respectively. Cryptococcus neoformans was demonstrated to form biofilms in polystyrene microtiter plates. The numbers of CFU of disaggregated biofilms, 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide reduction, and light and confocal microscopy were used to measure the fungal mass, the metabolic activity, and the appearance of C. neoformans biofilms, respectively. Biofilm development by C. neoformans followed a standard sequence of events: fungal surface attachment, microcolony formation, and matrix production. The susceptibilities of C. neoformans cells of the biofilm and planktonic phenotypes to four antifungal agents were examined. The exposure of C. neoformans cells or preformed cryptococcal biofilms to fluconazole or voriconazole did not result in yeast growth inhibition and did not affect the metabolic activities of the biofilms, respectively. In contrast, both C. neoformans cells and preformed biofilms were susceptible to amphotericin B and caspofungin. However, C. neoformans biofilms were significantly more resistant to amphotericin B and caspofungin than planktonic cells, and their susceptibilities to these drugs were further reduced if cryptococcal cells contained melanin. A spot enzyme-linked immunosorbent assay and light and confocal microscopy were used to investigate how antifungal drugs affected C. neoformans biofilm formation. The mechanism by which amphotericin B and caspofungin interfered with C. neoformans biofilm formation involved capsular polysaccharide release and adherence. Our results suggest that biofilm formation may diminish the efficacies of some antifungal drugs during cryptococcal infection.

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