EUCAST Broth Microdilution Method Research Articles

Characterization of Yeast Isolated from the Gut Microbiota of Tunisian Children with Autism Spectrum Disorder.

Research on the microbiota-gut-brain axis in autism has primarily focused on bacteria, with limited attention to fungi. There is a growing interest in understanding the involvement of fungi, particularly Candida, in patients with autism spectrum disorder. The aim of this study was to assess the prevalence, antifungal susceptibility profiles and virulence factors of Candida isolates from the guts of Tunisian children with autism. Twenty-eight children with autism and forty-six controls were enrolled. Candida isolates from the faecal samples were identified using biochemical and molecular methods; antifungal susceptibility testing was determined by the EUCAST broth microdilution method and virulence factors, including biofilm formation, cell surface hydrophobicity and phospholipase and proteinase activities, were assessed in vitro. As a result, Candida was detected in 13 children with autism (46.4%) and 14 control children (30.4%). Candida albicans was found to be the most common species isolate in the faeces of both groups of children. Antifungal susceptibility profiles showed that one Candida isolate was resistant to amphotericin B and anidulafungin (3.7%), six were resistant to micafungin (22.2%) and five were resistant to fluconazole (18.5%). All Candida isolates were biofilm producers. Of the twenty-seven isolates, only four showed phospholipase activity (14.8%), eight showed aspartyl-proteinase activity (29.6%) and nine were hydrophobic (33.3%). These results highlight the presence of Candida in the guts of children with autism, as well as the ability to express multiple virulence factors and the antifungal resistance, and they emphasize the need for further studies to confirm intestinal Candida colonization and its potential role in autism.

Emergence of Clonally-Related South Asian Clade I Clinical Isolates of Candida auris in a Greek COVID-19 Intensive Care Unit.

Candida auris has recently emerged as a multidrug-resistant yeast implicated in various healthcare-associated invasive infections and hospital outbreaks. In the current study, we report the first five intensive care unit (ICU) cases affected by C. auris isolates in Greece, during October 2020-January 2022. The ICU of the hospital was converted to a COVID-19 unit on 25 February 2021, during the third wave of COVID-19 in Greece. Identification of the isolates was confirmed by Matrix Assisted Laser Desorption Ionization Time of Flight mass spectroscopy (MALDI-TOF]. Antifungal susceptibility testing was performed by the EUCAST broth microdilution method. Based on the tentative CDC MIC breakpoints, all five C. auris isolates were resistant to fluconazole (≥32 μg/mL), while three of them exhibited resistance to amphotericin B (≥2 μg/mL). The environmental screening also revealed the dissemination of C. auris in the ICU. Molecular characterization of C. auris clinical and environmental isolates was performed by MultiLocus Sequence Typing (MLST) of a set of four genetic loci, namely ITS, D1/D2, RPB1 and RPB2, encoding for the internal transcribed spacer region (ITS) of the ribosomal subunit, the large ribosomal subunit region and the RNA polymerase II largest subunit, respectively. MLST analysis showed that all isolates possessed identical sequences in the four genetic loci and clustered with the South Asian clade I strains. Additionally, PCR amplification and sequencing of the CJJ09_001802 genetic locus, encoding for the "nucleolar protein 58" that contains clade-specific repeats was performed. Sanger sequence analysis of the TCCTTCTTC repeats within CJJ09_001802 locus also assigned the C. auris isolates to the South Asian clade I. Our study confirms that C. auris is an emerging yeast pathogen in our region, especially in the setting of the ongoing COVID-19 worldwide pandemic. Adherence to strict infection control is needed to restrain further spread of the pathogen.

In vitro activity of isavuconazole against clinically relevant Trichosporon species: a comparative evaluation of EUCAST broth microdilution and MIC Test Strip methods.

To evaluate the in vitro activity of isavuconazole on 154 clinical and reference strains of Trichosporon asahii, Trichosporon asteroides, Trichosporon coremiiforme, Trichosporon faecale and Trichosporon inkin by using the EUCAST broth microdilution method (BMD) and Liofilchem MIC Test Strips (MTS). Antifungal susceptibility testing for isavuconazole, fluconazole, voriconazole and posaconazole was assessed by EUCAST E.DEF 7.3.2. MIC values of isavuconazole obtained by BMD after 48 h of incubation were compared with MTS MICs after 24 and 48 h of incubation. T. asahii and T. asteroides showed the highest isavuconazole MIC90 values (0.5 mg/L). In clinical isolates, T. asahii exhibited the highest MIC90 values (0.5 mg/L) compared with non-T. asahii (0.06-0.25 mg/L). The five non-WT T. asahii isolates for fluconazole, voriconazole and posaconazole also exhibited high MICs of isavuconazole (≥0.5 mg/L). A better correlation between MTS and BMD MICs was observed after 24 h incubation for all species tested. MTS measurements performed at 48 h increased by at least 122% the number of isolates with >2 dilutions compared with the standard method. Isavuconazole exhibited variable in vitro activity among the Trichosporon species tested, showing higher or equal MICs than the other azoles. The five non-WT T. asahii clinical isolates tested also exhibited high isavuconazole MICs, suggesting the occurrence of triazole cross-resistance. Our MTS data indicate that there is no advantage in extended reading time for MTS from 24 to 48 h for Trichosporon yeasts.

In Vitro Antifungal Activity of Ibrexafungerp (SCY-078) Against Contemporary Blood Isolates From Medically Relevant Species of Candida: A European Study.

BackgroundIbrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis.ObjectiveThe aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida.MethodsIbrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated.ResultsIbrexafungerp MICs ranged from 0.016 to ≥8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016–0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06–≥8 mg/L). Modal MICs/MIC50s (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis.ConclusionIbrexafungerp showed a potent in vitro activity against Candida.

Spectrophotometric detection of azole-resistant Aspergillus fumigatus with the EUCAST broth microdilution method: is it time for automated MIC reading of EUCAST antifungal susceptibility testing of Aspergillus species?

Current reference susceptibility testing methods of Aspergillus require visual reading, which is subjective and necessitates experienced staff. We compared spectrophotometric and visual MIC reading of EUCAST E.Def 9.3.2 susceptibility testing of Aspergillus fumigatus for a large collection of isolates with different azole resistance mechanisms. A. fumigatus (n = 200) were examined, including 62 WT and 138 non-WT with the following alterations: TR34/L98H (n = 57), TR46/Y121F/T289A (n = 54) or single point mutations (n = 27). EUCAST E.Def 9.3.2 susceptibility testing was performed for amphotericin B, itraconazole, voriconazole, posaconazole and isavuconazole. MICs were determined after 48 h of incubation visually and spectrophotometrically, as the lowest concentration corresponding to a 1%, 3%, 5%, 10% or 15% OD increase above the background OD. The best spectrophotometric endpoint (SPE) was identified based on the highest essential agreement (EA; ±1 two-fold dilution) and categorical agreement (CA) and fewer very major errors (VMEs) and major errors (MEs). Τhe best SPEs were 5% and 10% for all drugs. The best agreement between visual and spectrophotometric MICs was found with the 10% growth endpoint, which resulted in identical median MICs with 90% of differences being ≤1 two-fold and higher EA (91%-100%) and CA (100%) and no VMEs and MEs compared with the 5% endpoint (77%-100%, 96%-98%, 0% and 0%-4%, respectively). Spectrophotometric MIC reading can be used for A. fumigatus susceptibility testing and for detecting azole resistance. A visual inspection of the plate should be performed to confirm equal inoculation, absence of well contamination and proper growth, and to identify potential uncommon phenotypes or subpopulations.

Azole resistance in Aspergillus fumigatus isolates from respiratory specimens in Lyon University Hospitals, France: prevalence and mechanisms involved

Resistance of Aspergillus fumigatus to triazoles has been reported increasingly in Europe. As few data are available from Southern France, the objectives of this study were to assess the burden of A. fumigatus isolates with azole resistance from clinical specimens in Lyon, and explore the resistance mechanisms involved. In this retrospective cross-sectional study, 221 consecutive A. fumigatus isolates from respiratory samples were identified from an 8-month period from 195 patients attending the Pulmonary Medicine Departments of Lyon University Hospitals. Morphological identification was confirmed by sequence analysis of the β-tubulin gene. All samples were tested for susceptibilities to itraconazole, voriconazole, posaconazole and isavuconazole using concentration gradient strips, and the results were confirmed using the EUCAST broth microdilution method. Resistance mechanisms were investigated by sequencing the cyp51A gene and its promoter, and by expression analysis of cyp51 and genes encoding several efflux transporters. Four isolates exhibited azole resistance. Three isolates presented with polymorphisms in an intronic region of cyp51A, and one isolate had F46Y, M172V and E427K polymorphisms. No mutations were identified in the cyp51A promoter, but significant induction of cyp51A and cyp51B gene expression was observed for all four and three isolates, respectively. Significant induction of atrF and cdr1B gene expression was observed for two and three isolates, respectively. No significant induction of MDR1/2/3/4, MFS56 and M85 gene expression was observed. To conclude, the observed prevalence of azole resistance was 2.1%. Significant induction of expression of the cyp51 genes and two genes encoding efflux transporters was evidenced, underlying the diversity of resistance mechanisms to be explored.

Antifungal Resistance in Isolates of Aspergillus from a Pig Farm

Antibiotic resistance in fungal isolates is increasing on a global scale. Despite knowledge that pig farmers are occupationally exposed to infectious species of fungi, such as Aspergillus spp., little is known regarding their potential exposure to antifungal-resistant Aspergillus spp. The aim of this study is to obtain knowledge regarding the antifungal resistance profiles of isolates of Aspergillus species taken from different source materials—including airborne dust, surface dust, faeces, and straw—within a pig farm. The EUCAST broth microdilution method was used for testing antifungal resistance from 43 isolates of Aspergillus sampled in 3 periods inside a Danish pig farm. Seven species of Aspergillus were obtained, including A. candidus (n = 5), A. fumigatus (n = 5), A. glaucus (n = 13), A. nidulans (n = 2), A. niger (n = 15), A. terreus (n = 1), and A. versicolor (n = 2). Overall, 27.9% of the Aspergillus isolates displayed resistance against at least one antifungal, and 11.6% of Aspergillus isolates displayed resistance against multiple antifungals. The most abundant group exhibiting antifungal resistance was affiliated with the species A. niger, with isolates exhibiting resistance to itraconazole, voriconazole, and caspofungin. One isolate of A. glaucus and two isolates of A. versicolor were resistant to amphotericin B (MIC ≥ 2 mg/L amphotericin B). Antibiotic-resistant fungi were found on all three sampling days.

In vitro activity of dalbavancin against Gram-positive bacteria isolated from diabetic foot osteomyelitis.

Diabetic foot infections (DFIs) represent a serious threat to public health because of their frequency and the severity of their consequences, i.e. osteomyelitis and amputation. The management of diabetic foot osteomyelitis (DFOM) requires prolonged antibiotic therapy. In Western countries, Gram-positive bacteria are the most commonly encountered pathogens. This study evaluated the in vitro activity of dalbavancin, a novel lipoglycopeptide with extended half-life, recently marketed in Europe for acute bacterial skin and skin structure infections, on a panel of Gram-positive bacteria responsible for DFOM. Dalbavancin activity was evaluated against a panel of Gram-positive bacterial strains isolated from bone biopsies performed by a trained surgeon among patients with suspected DFOM. MICs were determined using MIC Test Strips (Liofilchem) and confirmed with the EUCAST broth microdilution method. Three other antimicrobial agents (vancomycin, teicoplanin and ceftobiprole) were used as comparators. Dalbavancin showed excellent activity against all Gram-positive bacterial strains tested, including one teicoplanin-resistant Staphylococcus epidermidis isolate. With MIC50 and MIC90 values of 0.047 and 0.094 mg/L, respectively, dalbavancin showed the most potent in vitro activity among antimicrobial agents tested. With its efficacy, good tolerability and unique pharmacokinetic properties, dalbavancin appears to be a promising treatment for DFOM involving Gram-positive bacteria.

Yarrowia lipolytica causes sporadic cases and local outbreaks of infections and colonisation.

Yarrowia lipolytica belongs to the normal human microbiota but is also found in substrates with high contents in lipids and used in biotechnological processes. It is sometimes reported as human pathogen and especially in catheter-related candidaemia. Two apparently grouped cases of infections and/or contamination were reported involving 3 and 9 patients, respectively, in two hospitals. The goal of this study was to design a molecular tool to study the genetic diversity of Ylipolytica and confirm or not the common source of contamination during these grouped cases. Given that there is no genotyping method, we used genomic markers assessed on environmental isolates to determine intra-species relationship. We selected five highly polymorphic intergenic regions, totalling more than 3200bp and sequenced them for clinical (n=20) and environmental (n=14) isolates. Antifungal susceptibility was determined by EUCAST broth microdilution method. Multiple alignment of the five sequences revealed divergence of 0%-5.8% between isolates as compared to approximately 0.2%-0.25% after alignment of whole genomes, suggesting their potential usefulness to establish genetic relatedness. The analysis showed the multiple origins of the isolates. It uncovered two grouped case of fungaemia involving 3 and 2 patients, respectively. It also revealed several unrelated sporadic cases despite their temporal relationship and one probable laboratory contamination by a common yet uncovered source, explaining several consecutive positive cultures without infection. All isolates had high minimal inhibitory concentration (MIC) for flucytosine, the majority (14/34) was susceptible to fluconazole, and all to the other antifungal agents tested. This method could help elucidate cases related to the opportunistic pathogen Y lipolytica.

The Effect of Posaconazole, Itraconazole and Voriconazole in the Culture Medium on Aspergillus fumigatus Triazole Resistance

Triazoles are the only compounds used as antibiotics in both medicine and agriculture. The presence of triazoles in the environment can contribute to the acquisition of azole resistance among isolates of Aspergillus fumigatus. The objective of this study was to investigate the effect of A. fumigatus exposure to triazoles on susceptibility to these compounds. Seventeen triazole-resistant and 21 triazole-sensitive A. fumigatus isolates were examined. The isolates were transferred 20 times on the Sabouraud medium supplemented with posaconazole, itraconazole or voriconazole, followed by five times on the medium not supplemented. The minimum inhibitory concentrations of antimycotics were examined according to the EUCAST broth microdilution method after the 20th transfer and also the 25th transfer. In addition, the expression levels of genes mdr1, mdr2, mdr3, atrF, cyp51A and cyp51B were determined. Cultivation of A. fumigatus on media supplemented with posaconazole, itraconazole and voriconazole resulted in the acquisition of resistance to the tested triazoles of all examined isolates. After recultivation on Sabouraud without azoles, most of the isolates lost their acquired resistance. The long-term use of triazole compounds in agriculture may result in the occurrence of triazole resistant A. fumigatus isolates in the environment, not only by induction or selection of mutations in the cyp51A gene, but also by contribution to changes in the gene expression.

Microsatellite Typing and Antifungal Susceptibility of Candida glabrata Strains Isolated From Patients With Candida Vaginitis.

Vulvovaginal candidiasis (VVC) is a yeast infection with a global reach and millions of dollars are spent annually for its diagnosis and treatment. Recently, Candida glabrata with different degrees of antifungal resistance has been considered as the second most common cause of vaginal infections. The aim of the present study is to determine the antifungal susceptibility and molecular epidemiology profiles of C. glabrata isolates from patients with VVC. Sixty-one C. glabrata isolates were examined for antifungal susceptibility using the EUCAST broth microdilution method. Moreover, microsatellite length polymorphism (MLP) was used for typing the C. glabrata isolates using six microsatellite markers. Overall, 13, 3.3, and 0% of the isolates were non-wild types to itraconazole, posaconazole, and voriconazole, respectively. Sixty (98.4%) isolates were an intermediate phenotype to fluconazole and only one isolate was fluconazole resistant. Microsatellite length polymorphism with a discriminatory power of 0.964 identified 35 distinct types and 24 singleton genotypes. The assessment of the population genetic structure revealed that the non-wild-type population had a moderate genetic differentiation compared to the wild type population (FST = 0.1457). It was also found that the most common genotypes were G27 (eight strains), G12 (six strains), and G4 (five strains). We found that eight strains were resistant/a non-wild phenotype to itraconazole. Five out of eight (62.5%) resistant/non-wild phenotype strains correlated to a predominant genotype (GT27) and the rest belonged to GT11 (12.5%), GT29 (12.5%), and GT28 (12.5%). The current study is the first molecular epidemiology study in the southwest of Iran and demonstrates the antifungal susceptibility profiles of C. glabrata in it. This study shows a wide range of the genetic diversity of C. glabrata (35 different genotypes) from VVC in the southwest of Iran. The majority of the non-wild isolates had a dominant genotype or genotypes related to this dominant genotype (clonal cluster one).

Antifungal susceptibility profiles of rare ascomycetous yeasts.

To generate antifungal susceptibility patterns for Trichomonascus ciferrii (Candida ciferrii), Candida inconspicua (Torulopsis inconspicua) and Diutina rugosa species complex (Candida rugosa species complex), and to provide key parameters such as MIC50, MIC90 and tentative epidemiological cut-off values (TECOFFs). Our strain set included isolates of clinical origin: C. inconspicua (n = 168), D. rugosa species complex (n = 90) [Candida pararugosa (n = 60), D. rugosa (n = 26) and Candida mesorugosa (n = 4)], Pichia norvegensis (Candida norvegensis) (n = 15) and T. ciferrii (n = 8). Identification was performed by MALDI-TOF MS or internal transcribed spacer sequencing. Antifungal susceptibility patterns were generated for azoles, echinocandins and amphotericin B using commercial Etest and the EUCAST broth microdilution method v7.3.1. Essential agreement (EA) was calculated for Etest and EUCAST. C. inconspicua, C. pararugosa and P. norvegensis showed elevated azole MICs (MIC50 ≥0.06 mg/L), and D. rugosa and C. pararugosa elevated echinocandin MICs (MIC50 ≥0.06 mg/L). EA between methods was generally low (<90%); EA averaged 77.45%. TECOFFs were suggested for C. inconspicua and D. rugosa species complex. Rare yeast species tested shared high fluconazole MICs. D. rugosa species complex displayed high echinocandin MICs, while C. inconspicua and P. norvegensis were found to have high azole MICs. Overall, the agreement between EUCAST and Etest was poor and therefore MIC values generated with Etest cannot be directly compared with EUCAST results.

In Vitro Activity of a New Oral Glucan Synthase Inhibitor (MK-3118) Tested against Aspergillus spp. by CLSI and EUCAST Broth Microdilution Methods

MK-3118, a glucan synthase inhibitor derived from enfumafungin, and comparator agents were tested against 71 Aspergillus spp., including itraconazole-resistant strains (MIC, ≥ 4 μg/ml), using CLSI and EUCAST reference broth microdilution methods. The CLSI 90% minimum effective concentration (MEC(90))/MIC(90) values (μg/ml) for MK-3118, amphotericin B, and caspofungin, respectively, were as follows: 0.12, 2, and 0.03 for Aspergillus flavus species complex (SC); 0.25, 2, and 0.06 for Aspergillus fumigatus SC; 0.12, 2, and 0.06 for Aspergillus terreus SC; and 0.06, 1, and 0.03 for Aspergillus niger SC. Essential agreement between the values found by CLSI and EUCAST (± 2 log(2) dilution steps) was 94.3%. MK-3118 was determined to be a potent agent regardless of the in vitro method applied, with excellent activity against contemporary wild-type and itraconazole-resistant strains of Aspergillus spp.

Activity of MK-3118, a new oral glucan synthase inhibitor, tested against Candida spp. by two international methods (CLSI and EUCAST)

To evaluate the activity of the orally bioavailable enfumafungin derivative MK-3118 and comparator antifungal agents tested against a collection of 113 clinical isolates of Candida spp. using CLSI and EUCAST broth microdilution (BMD) methods. Candida spp. isolates (n=113) were tested by CLSI and EUCAST methods. The collection contained 29 Candida albicans, 29 Candida glabrata, 21 Candida tropicalis, 15 Candida parapsilosis and 19 Candida krusei, including azole- and echinocandin-resistant isolates. CLSI and EUCAST MIC endpoints of 50% and 100% inhibition were determined using visual reading at 24 and 48 h of incubation and spectrophotometric reading at 24 h of incubation, respectively. MK-3118 CLSI MIC results ranged from 0.06 to 16 mg/L depending on species, duration of incubation and endpoint criteria (EC) used. Comparison of CLSI and EUCAST following 24 h of incubation and either 50% or 100% inhibition revealed an essential agreement (EA; ± 2 doubling dilutions) of 99.1% using the 50% inhibition EC and 93.2% using the 100% inhibition EC. MK-3118 (24 h of incubation and 50% EC) was active against all the species tested and displayed similar potency to caspofungin (using CLSI BMD) against C. albicans (MIC90, 1 and 2 mg/L, respectively), C. tropicalis (1 and 1 mg/L, respectively), C. parapsilosis (0.5 and 0.5 mg/L, respectively) and C. krusei (2 and 1 mg/L, respectively), but was 8-fold more potent than caspofungin against C. glabrata strains (MIC90, 2 and 16 mg/L, respectively). MK-3118 was active against fluconazole-resistant strains as well as caspofungin-resistant strains with documented fks mutations. MK-3118 was documented to have potent in vitro activity against Candida spp. when tested by both CLSI and EUCAST BMD methods, with the highest overall EA (99.1%) obtained when MK-3118 MIC results were read after 24 h of incubation using a partial inhibition EC (50%).

Coexistence of blaOXA-23 with blaNDM-1 and armA in clinical isolates of Acinetobacter baumannii from India

Sir, The production of carbapenemases is the most common mechanism responsible for carbapenem resistance in Acinetobacter baumannii. They include metallo-b-lactamases (VIM, IMP and SIM types), which have been sporadically reported in some parts of the world, and acquired OXA-type carbapenemases which have been more frequently identified worldwide and are clustered in three major subfamilies (blaOXA-23, blaOXA-24 and blaOXA-58). 1 High levels of resistance to aminoglycosides due to the production of plasmid-encoded 16S rRNA methylase in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter spp. have been documented since 2003. The present study was undertaken to determine the mechanism responsible for the carbapenem resistance. Three carbapenem-non-susceptible A. baumannii were isolated from patients in the intensive care unit of a tertiary care hospital in Chennai, India in April 2010. Species identification and antibiotic testing were carried out using an automated machine (VITEK-2). The MICs of carbapenems and aminoglycosides were determined using the CLSI agar dilution method, while tigecycline MICs were determined using the EUCAST broth microdilution method. All the isolates were resistant to all the b-lactams, aminoglycosides and quinolones, and were only susceptible to tigecycline and colistin. Double disc synergy test (DDST) and modified Hodge test (MHT) were used for detection of metallo-b-lactamases and other carbapenemases, respectively. PCR screening was performed for OXA-type carbapenemases (blaOXA-23, -24, -51 and -58-like) and the known metallo-b-lactamase genes. 3 – 5 All three isolates showed positivity for both DDST and MHT, and PCR yielded the products with expected sizes for blaOXA-51, 23-like and blaNDM-1 (Table 1). Sequencing of both blaOXA-23 and blaNDM-1 genes showed 100% identities with previously reported genes. In all three isolates, the blaOXA-23 gene was adjacent to insertion element ISAba1, which provides the promoter required for expression of linked resistance genes; blaOXA-51-like genes were also found in all of the isolates, but were not activated by ISAba1. Conjugation experiments using Escherichia coli J53 as the recipient were unsuccessful. Plasmids of Enterobacteriaceae were not detected among A. baumannii by PCR-based replicon typing. Susceptibility testing showed increased MICs of carbapenems and an unusual phenotype of broad-spectrum high-level resistance to aminoglycosides, including amikacin, gentamicin, netilmicin and tobramycin (MICs.256 mg/L), with susceptibility to tigecycline (MIC1⁄40.5–1 mg/L). PCR screening was performed for 16S rRNA methylase-encoding genes (armA, rmtA, rmtB, rmtC, rmtD and npmA). – 9 All three isolates showed positivity for the armA gene (Table 1). NDM-1 metallo-b-lactamase-mediated resistance to carbapenems in Enterobacteriaceae has been found in many parts of India. However, to our knowledge, this is the first

In vitroeffect of DNA topoisomerase inhibitors onCandida albicans

In this study we investigated the in vitro antifungal activity of 10 DNA topoisomerase inhibitors on the growth of Candida albicans. The EUCAST broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of the compounds for C. albicans. In addition, the effect of the inhibitors on the growth mode of C. albicans was investigated by light microscopy imaging. Of the 10 DNA topoisomerase inhibitors tested, only the anti-cancer drug aclarubicin displayed antifungal activity with a determinable MIC value of 8.4 microg/ml (10.3 microM). Aclarubicin was also active against clinical isolates of C. albicans with MIC values ranging between 0.8 and 7.3 microg/ml (1-9 microM). Vitality assays showed that the action of aclarubicin was fungistatic. Four other DNA topoisomerase inhibitors, daunorubicin, doxorubicin, idarubicin and beta-lapachone, affected the morphology of C. albicans. The first three inhibitors encouraged the fungus to grow predominantly in the yeast form, whereas beta-lapachone caused hyphal proliferation. The results of this study indicate that some DNA topoisomerase inhibitors effect the growth and morphology of C. albicans suggesting a possible role as antifungal agents in the treatment of C. albicans infections.

P1973 Comparison of RPMI and AM3 medium for in vitro susceptibility testing of caspofungin against Candida spp. by EUCAST broth microdilution method

P1973 Comparison of RPMI and AM3 medium for in vitro susceptibility testing of caspofungin against Candida spp. by EUCAST broth microdilution method