Candida parapsilosis is an important pathogen of healthcare-associated bloodstream infections (BSI) causing high mortality and morbidity in immunocompromised patients in addition to other Candida species including C. albicans, C. tropicalis, C. glabrata, and C. krusei. Knowledge on recent local species distribution and trend is essential. An increase in the proportion of C. parapsilosis candidemia has been recently observed as a result of many risk factors. The distribution of candidemia has been changing in the last three decades. To determine the proportion of different Candida species causing candidemia in a tertiary-care hospital during January 2001 - December 2018, a retrospective study performed in a 853-bedded tertiary-care hospital in north-eastern Malaysia. All cases of candidemia from January-2001 to December-2018 were included, and the review was performed based on patients' medical records and laboratory database. The frequency of different Candida species was determined. This study showed that out of 1175 patients with candidemia, C. parapsilosis was the most common species contributing to 29.2% (343/1175) of candidemia, followed by C. albicans 20.1% (236/1175), C. tropicalis 18.7% (220/1175), C. glabrata 6.0% (71/1175), C. guilliermondii 3.7% (43/1175), C. rugosa 1.9% (22/1175), C. famata 1.7% (20/1175), C. krusei 1.4% (16/1175), C. dubliniensis 0.8% (9/1175), C. lusitaniae 0.7% (8/1175), C. lipolytica 0.3% (4/1175), C. pelliculosa 0.3% (4/1175), C. haemulonii, C. kefyr, C. utilis and C. inconspicua (1/1175 each). In addition, 14.9% (175/1175) belonged to Candida spp. which were not identified to species level. In conclusion, a different scenario for the proportion of Candida species with C. parapsilosis predominates over C. albicans as a nosocomial pathogen leading to candidemia has been shown in this study.
Candida auris is an emerging pathogenic yeast responsible for nosocomial infections with high mortality, on a global scale. A 65-year-old woman with hypovolemic shock and severe metabolic acidosis was intubated and admitted to the intensive care unit (ICU). Shortly after admission, she developed ventilator-associated pneumonia caused by multidrug-resistant Acinetobacter baumannii, which necessitated treatment with high-dose ampicillin-sulbactam. Two weeks later, a yeast was cultured from her blood. It formed pale pink colonies on CHROMagar Candida medium and produced predominantly oval budding yeast cells with the occasional rudimentary pseudohyphae on cornmeal agar. ID 32 C identified the yeast as Candida sake However, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and sequencing of the D1/D2 region of the 28S rRNA gene identified the yeast as C. auris.
The aims of this study were to compare the genetic relatedness of: (i) sequential and single isolates of Candida strains from women with recurrent vaginal candidiasis (RVC); and (ii) Candida strains from women who had only one episode of infection within a 1-year period. In total, 87 isolates from 71 patients were cultured, speciated and genotyped by random amplification of polymorphic DNA (RAPD) analysis. Patients were categorized into three groups, namely those with: (i) a history of RVC from whom two or more yeast isolates were obtained (group A); (ii) a history of RVC from whom only a single isolate was obtained (group B); and (iii) a single episode of vaginal candidiasis within a 1-year period (group C). Six yeast species were detected: Candida albicans, Candida glabrata, Candida lusitaniae, Candida famata, Candida krusei and Candida parapsilosis. Interestingly, the prevalence of non-albicans species was higher in group A patients (50 %) than in patients in groups B (36 %) or C (18.9 %). Eighty RAPD profiles were observed, with a total of 61 polymorphic PCR fragments of distinct sizes. Clustering analysis showed that, overall, the majority of patients in group A had recurrent infections caused by highly similar, but not identical, sequential strains [mean pairwise similarity coefficient (S(AB)) = 0.721 +/- 0.308]. The range of mean S(AB) values for intergroup comparisons for C. albicans isolates alone was 0.50-0.56, suggesting that there was no significant relatedness between strains from different groups. Genetic similarity of C. albicans isolates from patients in group A was lower than that of C. albicans isolates from patients in group C (mean S(AB) = 0.532 +/- 0.249 and 0.636 +/- 0.206, respectively); this difference was statistically significant (P = 0.036). These results demonstrate that the cause of recurrent infections varies among individuals and ranges between strain maintenance, strain microevolution and strain replacement; the major scenario is strain maintenance with microevolution. They also show that C. albicans strains that cause recurrent infections are less similar to each other than strains that cause one-off infections, suggesting that the former may represent more virulent subtypes.
A total of 2,153 high vaginal swabs were processed for the presence of yeasts. The specimens were obtained from pregnant and non-pregnant Malaysian women with and without vaginitis. The yeast species most commonly isolated were Candida albicans, C. glabrata, C. famata and C. parapsilosis. C. albicans was isolated from 27% of pregnant women with vaginitis, 14% of pregnant women with no overt vaginitis, 15% of non-pregnant women with vaginitis, and 3% of non-pregnant women with no vaginitis. The significant difference of the isolation rates from women with and without vaginitis indicates that C. albicans is likely to be a vaginal pathogen.
The distribution of Candida species was examined using 1114 yeasts isolated from various clinical specimens. The isolates were identified by germ tube test, hyphal/pseudohyphae and chlamydoconidia production and carbohydrate assimilation test using ten carbohydrates (glucose, sucrose, trehalose, cellobiose, arabinose, galactose, mannitol, raffinose, lactose and maltose). Among the 1114 isolates studied, 9 species of Candida were identified and the relative frequency of isolation was C. albicans (44.2%), C. parapsilosis (26.0%), C. tropicalis (17.7%), C. glabrata (9.6%), C. krusei (1.2%), C. rugosa (0.6%), C. guilliermondii (0.2%), C. lusitaniae (0.08%) and C. kefyr (0.08%). Non-C. albicans was the most common Candida species isolated from blood, respiratory system, urine and skin. The isolate from vaginal swabs was predominantly C. albicans. 82.2% of C. glabrata and 64.2% of C. krusei isolated in this study were from vaginal swabs.
Oral Candida colonisation is higher in tobacco smokers as compared to non-smokers; however, it remains unknown whether smokeless tobacco chewers are susceptible to increased oral Candida colonisation. The aim was to determine the oral Candida carriage and species prevalence amongst habitual gutka-chewers and non-chewers in a cohort from Karachi, Pakistan. Forty-five gutka-chewers and 45 non-chewers were included. Information regarding age, sex, duration of gutka-chewing habit, daily frequency of gutka consumption, duration of holding gutka in the mouth, daily frequency of tooth-brushing and tongue brushing was collected using a questionnaire. Oral yeast samples were collected by scraping the dorsum of the tongue and bilateral buccal mucosa with a sterile cotton swab. Identification of yeast species was performed using standard techniques. Tongue lesions were identified and recorded. Unstimulated whole salivary flow rate (UWSFR) was also measured. There was no significant difference in the mean age, UWSFR and oral Candida carriage among gutka-chewers and non-chewers. Individuals were chewing gutka since 4·4 years and were consuming five gutka sachets daily. Candida albicans (C. albicans) was the most common yeast species isolated from 57·8% gutka-chewers and 64.4% non-chewers. In 24.4% gutka-chewers and 22·2% non-chewers, two candidal strains (C. albicans and Candida tropicalis) were isolated. In conclusion, the present results indicated no significant difference in oral Candida carriage in habitual gutka-chewers and non-chewers.
The objective of our study was to study the effectiveness of CHROMagar Candida™ as the primary identification method for various clinical Candida isolates, other than the three suggested species by the manufacturer. We studied 34 clinical isolates which were isolated from patients in a local teaching hospital and 7 ATCC strains. These strains were first cultured in Sabouraud dextrose broth (SDB) for 36 hours at 35ºC, then on CHROMagar plates at 30ºC, 35ºC and 37ºC. The sensitivity of this agar to identify Candida albicans, Candida dubliniensis, Candida tropicalis, Candida glabrata, Candida rugosa, Candida krusei and Candida parapsilosis ranged between 25 and 100% at 30ºC, 14% and 100% at 35ºC, 56% and 100% at 37ºC. The specificity of this agar was 100% at 30ºC, between 97% and 100% at 35ºC, 92% and 100% at 37ºC. The efficiency of this agar ranged between 88 and 100% at 30ºC, 83% and 100% at 35ºC, 88% and 100% at 37ºC. Each species also gave rise to a variety of colony colours ranging from pink to green to blue of different colony characteristics. Therefore, the chromogenic agar was found to be useful in our study for identifying clinical Candida isolates.
Candidiasis is a term describing infections by yeasts from the genus Candida, and the type of infection encompassed by candidiasis ranges from superficial to systemic. Treatment of such infections often requires antifungals such as the azoles, but increased use of these drugs has led to selection of yeasts with increased resistance to these drugs. In this study, we used allicin, an allyl sulfur derivative of garlic, to demonstrate both its intrinsic antifungal activity and its synergy with the azoles, in the treatment of these yeasts in vitro. In this study, the MIC(50) and MIC(90) of allicin alone against six Candida spp. ranged from 0.05 to 25 microg/ml. However, when allicin was used in combination with fluconazole or ketoconazole, the MICs were decreased in some isolates. Our results demonstrated the existing synergistic effect between allicin and azoles in some of the Candida spp. such as C. albicans, C. glabrata and C. tropicalis, but synergy was not demonstrated in the majority of Candida spp. tested. Nonetheless, In vivo testing needs to be performed to support these findings.
The in vitro antifungal susceptibilities of 159 clinical isolates of Candida species from patients with invasive candidiasis in Kuala Lumpur Hospital, Malaysia, were determined against amphotericin B, fluconazole, voriconazole, itraconazole and caspofungin. The most common species were Candida albicans (71 isolates), Candida parapsilosis (42 isolates), Candida tropicalis (27 isolates) and Candida glabrata (12 isolates). The susceptibility tests were carried out using an E-test. The MIC breakpoints were based on Clinical Laboratory Standards Institute criteria. Amphotericin B and voriconazole showed the best activities against all the isolates tested, with MIC(90) values of ≤1 µg ml(-1) for all major species. Only one Candida lusitaniae isolate was resistant to amphotericin B, and all the isolates were susceptible to voriconazole. In total, six isolates were resistant to fluconazole, comprising two isolates of C. albicans, two of C. parapsilosis, one C. tropicalis and one C. glabrata, and all of these isolates showed cross-resistance to itraconazole. The MIC(90) of itraconazole was highest for C. glabrata and C. parapsilosis. Caspofungin was active against most of the isolates except for five isolates of C. parapsilosis. The MIC(90) of caspofungin against C. parapsilosis was 3 µg ml(-1). In conclusion, amphotericin B remains the most active antifungal agent against most Candida species except for C. lusitaniae. Voriconazole is the best alternative for fluconazole- or itraconizole-resistant isolates. Although five of the C. parapsilosis isolates showed in vitro resistance to caspofungin, more clinical correlation studies need to be carried out to confirm the significance of these findings. Currently, despite the increase in usage of antifungals in our hospitals, especially in the management of febrile neutropenia patients, the antifungal-resistance problem among clinically important Candida isolates in Kuala Lumpur Hospital is not yet worrying. However, continued antifungal-susceptibility surveillance needs to be conducted to monitor the antifungal-susceptibility trends of Candida species and other opportunistic fungal pathogens.
This study was aimed at determining the phospholipase and haemolysin activity of Candida isolates in Malaysia. A total of 37 Candida clinical isolates representing seven species, Candida albicans (12), Candida tropicalis (8), Candida glabrata (4), Candida parapsilosis (1), Candida krusei (4), Candida orthopsilosis (1) and Candida rugosa (7) were tested. In vitro phospholipase activity was determined by using egg yolk plate assay whereas in vitro haemolysin activity was tested by using blood plate assay on sheep blood Sabouraud's dextrose agar (SDA) enriched with glucose. Phospholipase activity was detected in 75% (9 out of 12) of the C. albicans isolates. Among the 25 non- C. albicans Candida isolates, phospholipase activity was detected in only 24% of these isolates. The phospholipase activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.002). Haemolysin activity was detected in 100% of the C. albicans, C. tropicalis, C. glabrata, C. krusei, C. parapsilosis, and C. orthopsilosis isolates while 75% of the C. krusei isolates and 12.3% of the C. rugosa isolates showed haemolysin activity. The haemolytic activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.0001).The findings in this study indicate that C. albicans isolates in Malaysia may possess greater virulence potential than the non-albicans species.
Candida speciation is vital for epidemiology and management of candidiasis. Nonmolecular conventional methods often fail to identify closely related germ tube positive yeasts from clinical specimens. The present study was conducted to identify these yeasts and to highlight issues in conventional versus molecular methods of identification. A total of 98 germ tube positive yeasts from high vaginal swabs were studied over a 12-month period. Isolates were examined with various methods including growth at 42 °C and 45 °C on Sabouraud dextrose agar (SDA), color development on CHROMagar Candida medium, chlamydospore production on corn meal agar at 25 °C, carbohydrate assimilation using ID 32C system, and polymerase chain reaction using a single pair of primers targeting the hyphal wall protein 1 (Hwp1) gene. Of all the isolates studied, 97 were molecularly confirmed as C. albicans and one isolate was identified as C. dubliniensis. No C. africana was detected in this study. The molecular method used in our study was an accurate and useful tool for discriminating C. albicans, C. dubliniensis, and C. africana. The conventional methods, however, were less accurate and riddled with many issues that will be discussed in further details.
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.
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.
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.