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Isolates of the emerging pathogen Candida auris present in the UK have several geographic origins

Borman AM, Szekely A, Johnson EM

Med Mycol, 2017 Jul 01;55(5):563-567.
PMID: 28204557 DOI: 10.1093/mmy/myw147

Candida auris has recently emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide and the existence of geographic region-specific discrete clonal lineages. Here we have compared the rDNA sequences of 24 isolates of Candida auris from 14 different hospital centers in the United Kingdom with those of strains from different international origins present in the public sequence databases. Here we show that UK isolates of C. auris fall into three well-supported clades corresponding to lineages that have previously been reported from India, Malaysia and Kuwait, Japan and Korea, and South Africa, respectively.

Matched MeSH terms: Candida/isolation & purification
Candida vulturna pro tempore sp. nov., a dimorphic yeast species related to the Candida haemulonis species complex isolated from flowers and clinical sample

Sipiczki M, Tap RM

Int J Syst Evol Microbiol, 2016 Oct;66(10):4009-4015.
PMID: 27411802 DOI: 10.1099/ijsem.0.001302

In a taxonomic study of yeasts isolated from flowers in Cagayan de Oro, Mindenao Island, The Philippines, strains were identified as representing Kabatiella microsticta, Metschnikowia koreensis and a hitherto undescribed dimorphic species. Sequences of the D1/D2 domains of the LSU 26S rRNA genes, the internal transcribed spacer (ITS) regions and the SSU 18S rRNA genes were identical in the strains of the last-named group and differed from the corresponding sequences of the type strain of the closest related species, Candida duobushaemulonii, by 4 % (D1/D2), 7 % (ITS) and 1 % (SSU). In an independent study, a strain with D1/D2 and ITS sequences very similar to those of the Philippine strains was isolated in Malaysia from the blood of a patient dying of aspiration pneumonia. Both groups of isolates were moderately sensitive to anidulafungin, caspofungin, fluconazole, itraconazole and voriconazole but resistant to amphotericin B. Molecular phylogenetic analysis of the sequences placed the Philippine and Malaysian isolates close to the Candida haemulonis complex of Candida species. To reflect the geographical location of the sites of sample collection, the novel species name Candida vulturna pro tempore sp. nov. is proposed to accommodate these strains. The type strain is 11-1170T (=CBS 14366T=CCY 094-001-001T=NCAIM-Y02177T) isolated in Cagayan de Oro, The Philippines. Mycobank: MB 817222.

Matched MeSH terms: Candida/isolation & purification
Comparative Study of the Effects of Fluconazole and Voriconazole on Candida glabrata, Candida parapsilosis and Candida rugosa Biofilms

Madhavan P, Jamal F, Pei CP, Othman F, Karunanidhi A, Ng KP

Mycopathologia, 2018 Jun;183(3):499-511.
PMID: 29380188 DOI: 10.1007/s11046-018-0243-z

Infections by non-albicans Candida species are a life-threatening condition, and formation of biofilms can lead to treatment failure in a clinical setting. This study was aimed to demonstrate the in vitro antibiofilm activity of fluconazole (FLU) and voriconazole (VOR) against C. glabrata, C. parapsilosis and C. rugosa with diverse antifungal susceptibilities to FLU and VOR. The antibiofilm activities of FLU and VOR in the form of suspension as well as pre-coatings were assessed by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction assay. Morphological and intracellular changes exerted by the antifungal drugs on Candida cells were examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results of the antibiofilm activities showed that FLU drug suspension was capable of killing C. parapsilosis and C. rugosa at minimum inhibitory concentrations (MICs) of 4× MIC FLU and 256× MIC FLU, respectively. While VOR MICs ranging from 2× to 32× were capable of killing the biofilms of all Candida spp tested. The antibiofilm activities of pre-coated FLU were able to kill the biofilms at ¼× MIC FLU and ½× MIC FLU for C. parapsilosis and C. rugosa strains, respectively. While pre-coated VOR was able to kill the biofilms, all three Candida sp at ½× MIC VOR. SEM and TEM examinations showed that FLU and VOR treatments exerted significant impact on Candida cell with various degrees of morphological changes. In conclusion, a fourfold reduction in MIC50 of FLU and VOR towards ATCC strains of C. glabrata, C. rugosa and C. rugosa clinical strain was observed in this study.

Matched MeSH terms: Candida/isolation & purification
The inhibitory effects of aureobasidin A on Candida planktonic and biofilm cells

Tan HW, Tay ST

Mycoses, 2013 Mar;56(2):150-6.
PMID: 22882276 DOI: 10.1111/j.1439-0507.2012.02225.x

Aureobasidin A (AbA) is a cyclic depsipeptide antifungal compound that inhibits a wide range of pathogenic fungi. In this study, the in vitro susceptibility of 92 clinical isolates of various Candida species against AbA was assessed by determining the planktonic and biofilm MICs of the isolates. The MIC(50) and MIC(90) of the planktonic Candida yeast were 1 and 1 μg ml(-1), respectively, whereas the biofilm MIC(50) and MIC(90) of the isolates were 8 and ≥64 μg ml(-1) respectively. This study demonstrates AbA inhibition on filamentation and biofilm development of C. albicans. The production of short hyphae and a lack of filamentation might have impaired biofilm development of AbA-treated cells. The AbA resistance of mature Candidia biofilms (24 h adherent population) was demonstrated in this study.

Matched MeSH terms: Candida/isolation & purification
Occurrence and characterization of Candida nivariensis from a culture collection of Candida glabrata clinical isolates in Malaysia

Tay ST, Lotfalikhani A, Sabet NS, Ponnampalavanar S, Sulaiman S, Na SL, et al.

Mycopathologia, 2014 Oct;178(3-4):307-14.
PMID: 25022264 DOI: 10.1007/s11046-014-9778-9

BACKGROUND: Candida nivariensis and C. bracarensis have been recently identified as emerging yeast pathogens which are phenotypically indistinguishable from C. glabrata. However, there is little data on the prevalence and antifungal susceptibilities of these species.
OBJECTIVE: This study investigated the occurrence of C. nivariensis and C. bracarensis in a culture collection of 185 C. glabrata isolates at a Malaysian teaching hospital.
METHODS: C. nivariensis was discriminated from C. glabrata using a PCR assay as described by Enache-Angoulvant et al. (J Clin Microbiol 49:3375-9, 2011). The identity of the isolates was confirmed by sequence analysis of the D1D2 domain and internal transcribed spacer region of the yeasts. The isolates were cultured on Chromogenic CHROMagar Candida (®) agar (Difco, USA), and their biochemical and enzymic profiles were determined. Antifungal susceptibilities of the isolates against amphotericin B, fluconazole, voriconazole and caspofungin were determined using E tests. Clotrimazole MICs were determined using a microbroth dilution method.
RESULTS: There was a low prevalence (1.1 %) of C. nivariensis in our culture collection of C. glabrata. C. nivariensis was isolated from a blood culture and vaginal swab of two patients. C. nivariensis grew as white colonies on Chromogenic agar and demonstrated few positive reactions using biochemical tests. Enzymatic profiles of the C. nivariensis isolates were similar to that of C. glabrata. The isolates were susceptible to amphotericin B, fluconazole, voriconazole and caspofungin. Clotrimazole resistance is suspected in one isolate.
CONCLUSION: This study reports for the first time the emergence of C. nivariensis in our clinical setting.

Matched MeSH terms: Candida/isolation & purification*
Purification and comparison of intracellular proteinase A in Candida spp. isolates from Malaysian and Iranian patients and infected mice

Amri Saroukolaei S, Pei Pei C, Shokri H, Asadi F

J Mycol Med, 2012 Jun;22(2):149-59.
PMID: 23518017 DOI: 10.1016/j.mycmed.2012.01.002

To compare the specific intracellular proteinase A activity in clinical isolates of Candida species isolated from Iranian and Malaysian patients, the blood and kidneys of mice infected by Candida cells isolated from these human patients.

Matched MeSH terms: Candida/isolation & purification
Fulltext Distribution of Candida in the oral cavity and its differentiation based on the internally transcribed spacer (ITS) regions of rDNA

Zahir RA, Himratul-Aznita WH

Yeast, 2013 Jan;30(1):13-23.
PMID: 23208647 DOI: 10.1002/yea.2937

This study aimed to determine the distribution of Candida species in the oral cavity and differentiate the species based on PCR amplification, including HinfI and MspI digestion, in order to assess the effectiveness of using the rDNA region for species identification. Samples from saliva as well as palate, tongue and cheek mucosa surfaces were collected from 45 individuals, consisting of three groups: periodontal disease patients; denture-wearers; and the control group. The samples were serially diluted, spread on BHI and YPD agar plates and scored for colony-forming units (CFUs). Fifteen random candidal colonies were isolated and subjected to genomic DNA extraction, based on glass beads disruption. Four primers were used to amplify regions in the rDNA, and the ITSI-5.8S-ITSII PCR product was digested by HinfI and MspI restriction enzymes. The microbial loads on all sites of the denture-wearers were found to be significantly higher than control, while in the periodontal disease group only the microbial loads on the tongue were significantly higher than control. Meanwhile, there was no significant difference at other sites. The restriction fragment lengths of the clinical samples were compared to those of seven control species, allowing the differentiation of all seven species and the identification of 14 species from the clinical samples. The MspI restriction digest was not able to distinguish between C. albicans and C. dubliniensis, whereas the HinfI digest could not distinguish between C. tropicalis and C. parapsilosis. It was concluded that PCR-RFLP of the candidal rDNA region has potential for species identification. This study demonstrates the potential use of candidal rDNA as a means for identifying Candida species, based on genotype. The results also indicate the possibility of constructing genetic probes that target specific restriction fragments in the ITSI-5.8S-ITSII region, enabling swift and precise identification of Candida species.

Matched MeSH terms: Candida/isolation & purification
First isolation of Candida wangnamkhiaoensis from the blood of immunocompromised paediatric patient

Tap RM, Ho Betty LS, Ramli NY, Suppiah J, Hashim R, Sabaratnam P, et al.

Mycoses, 2016 Nov;59(11):734-741.
PMID: 27427490 DOI: 10.1111/myc.12509

Candida wangnamkhiaoensis is a species clustered under the Hyphopichia clade has not ever been isolated from any clinical specimens. To the best of our knowledge, this is the first report of C. wangnamkhiaoensis associated with fungaemia in immunocompromised paediatric patient. The isolate was assigned a strain name as UZ1679/14, in which the identification was confirmed by a polymerase chain reaction-sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) regions of the rRNA gene. Antifungal susceptibility pattern showed that the isolate was sensitive to anidulafungin, caspofungin, fluconazole and voriconazole. The patient clinically improved after the antifungal treatment with caspofungin.

Matched MeSH terms: Candida/isolation & purification*
Molecular differentiation and antifungal susceptibilities of Candida parapsilosis isolated from patients with bloodstream infections

Tay ST, Na SL, Chong J

J Med Microbiol, 2009 Feb;58(Pt 2):185-191.
PMID: 19141735 DOI: 10.1099/jmm.0.004242-0

The genetic heterogeneity and antifungal susceptibility patterns of Candida parapsilosis isolated from blood cultures of patients were investigated in this study. Randomly amplified polymorphic DNA (RAPD) analysis generated 5 unique profiles from 42 isolates. Based on the major DNA fragments of the RAPD profiles, the isolates were identified as RAPD type P1 (29 isolates), P2 (6 isolates), P3 (4 isolates), P4 (2 isolates) and P5 (1 isolate). Sequence analysis of the internal transcribed spacer (ITS) gene of the isolates identified RAPD type P1 as C. parapsilosis, P2 and P3 as Candida orthopsilosis, P4 as Candida metapsilosis, and P5 as Lodderomyces elongisporus. Nucleotide variations in ITS gene sequences of C. orthopsilosis and C. metapsilosis were detected. Antifungal susceptibility testing using Etests showed that all isolates tested in this study were susceptible to amphotericin B, fluconazole, ketoconazole, itraconazole and voriconazole. C. parapsilosis isolates exhibited higher MIC(50) values than those of C. orthopsilosis for all of the drugs tested in this study; however, no significant difference in the MICs for these two Candida species was observed. The fact that C. orthopsilosis and C. metapsilosis were responsible for 23.8 and 4.8 % of the cases attributed to C. parapsilosis bloodstream infections, respectively, indicates the clinical relevance of these newly described yeasts. Further investigations of the ecological niche, mode of transmission and virulence of these species are thus essential.

Matched MeSH terms: Candida/isolation & purification
Fulltext A Fatal Case of Candida auris and Candida tropicalis Candidemia in Neutropenic Patient

Mohd Tap R, Lim TC, Kamarudin NA, Ginsapu SJ, Abd Razak MF, Ahmad N, et al.

Mycopathologia, 2018 Jun;183(3):559-564.
PMID: 29383574 DOI: 10.1007/s11046-018-0244-y

We report a fatal case of Candida auris that was involved in mixed candidemia with Candida tropicalis, isolated from the blood of a neutropenic patient. Identification of both isolates was confirmed by amplification and sequencing of internal transcribed spacer and D1/D2 domain of large subunit in rRNA gene. Antifungal susceptibility test by E-test method revealed that C. auris was resistant to amphotericin B, anidulafungin, caspofungin, fluconazole, itraconazole and voriconazole. On the other hand, C. tropicalis was sensitive to all antifungal tested. The use of chromogenic agar as isolation media is vital in detecting mixed candidemia.

Matched MeSH terms: Candida/isolation & purification*
Epidemiology of candidemia and antifungal susceptibility in invasive Candida species in the Asia-Pacific region

Wang H, Xu YC, Hsueh PR

Future Microbiol, 2016 10;11:1461-1477.
PMID: 27750452

In the Asia-Pacific region, Candida albicans is the predominant Candida species causing invasive candidiasis/candidemia in Australia, Japan, Korea, Hong Kong, Malaysia, Singapore and Thailand whereas C. tropicalis is the most frequently encountered Candida species in Pakistan and India. Invasive isolates of C. albicans, C. parapsilosis complex and C. tropicalis remain highly susceptible to fluconazole (>90% susceptible). Fluconazole resistance (6.8-15%), isolates with the non-wild-type phenotype for itraconazole susceptibility (3.9-10%) and voriconazole (5-17.8%), and echinocandin resistance (2.1-2.2% in anidulafungin and 2.2% in micafungin) among invasive C. glabrata complex isolates are increasing in prevalence. Moreover, not all isolates of C. tropicalis have been shown to be susceptible to fluconazole (nonsusceptible rate, 5.7-11.6% in China) or voriconazole (nonsusceptible rate, 5.7-9.6% in China).

Matched MeSH terms: Candida/isolation & purification