Genetic relatedness among Candida tropicalis isolates from sporadic cases of fungemia in two university hospitals in Korea

Changes in the utilization patterns of antifungal agents, medical cost and clinical outcomes of candidemia from the health-care benefit expansion to include newer antifungal agents

OBJECTIVES

In 2014, South Korea expanded its national health insurance coverage to include newer antifungal agents, such as echinocandins. This study aimed to investigate the effects of policy change on the prescription patterns of antifungals, medical costs and clinical outcomes of candidemia.

METHODS

This retrospective cohort enrolled hospitalized patients with candidemia at three tertiary care hospitals in South Korea from January 2012 to December 2015. The utilization of antifungal agents, medical costs, length of hospital stay (LOS), and mortality before and after the health-care benefit expansion were compared, and the factors associated with all-cause 28-day mortality during the study period were analyzed.

RESULTS

A total of 769 candidemia cases were identified. The incidence of candidemia did not significantly vary during the study period (P = 0.253). The proportion of echinocandins, as the initial antifungal agent, and medical costs associated with candidemia significantly increased since the change in insurance coverage (P < 0.001). There was no significant difference in LOS and mortality associated with candidemia before and after the health-care benefit expansion (P =  0.696 and 0.931, respectively). Multivariate logistic regression analysis showed that initial treatment with caspofungin was associated with decreased mortality (adjusted odds ratio: 0.784; 95% confidence interval: 0.681-0.902; reference: fluconazole).

CONCLUSIONS

Although the utilization of newer antifungal agents and medical cost for candidemia has significantly increased since the health-care benefit expansion, there has been no change in the outcome of candidemia. However, the further increased use of newer antifungals may improve the outcome of candidemia in this country.

Ethnicity and Other Possible Risk Factors for Candidemia at 3 Tertiary Care University Hospitals in Hawaii

A total of 108 cases of candidemia detected in 3 tertiary care university hospitals in Hawaii between January 2001 and December 2002 were retrospectively reviewed. Candida albicans, Candida glabrata, and Candida tropicalis accounted for 28% of the cases. Mortality among Filipino patients was significantly higher than that among other ethnic groups (71% vs 48%; P<.05).

Resistance Mechanisms and Clinical Features of Fluconazole-Nonsusceptible Candida tropicalis Isolates Compared with Fluconazole-Less-Susceptible Isolates

We investigated the azole resistance mechanisms and clinical features of fluconazole-nonsusceptible (FNS) isolates of Candida tropicalis recovered from Korean surveillance cultures in comparison with fluconazole-less-susceptible (FLS) isolates. Thirty-five clinical isolates of C. tropicalis, comprising 9 FNS (fluconazole MIC, 4 to 64 μg/ml), 12 FLS (MIC, 1 to 2 μg/ml), and 14 control (MIC, 0.125 to 0.5 μg/ml) isolates, were assessed. CDR1, MDR1, and ERG11 expression was quantified, and the ERG11 and UPC2 genes were sequenced. Clinical features of 16 patients with FNS or FLS bloodstream isolates were analyzed. Both FNS and FLS isolates had >10-fold higher mean expression levels of CDR1, MDR1, and ERG11 genes than control isolates (P values of <0.02 for all). When FNS and FLS isolates were compared, FNS isolates had 3.4-fold higher mean ERG11 expression levels than FLS isolates (P = 0.004), but there were no differences in those of CDR1 or MDR1 Of all 35 isolates, 4 (2 FNS and 2 FLS) and 28 (8 FNS, 11 FLS, and 9 control) isolates exhibited amino acid substitutions in Erg11p and Upc2p, respectively. Both FNS and FLS bloodstream isolates were associated with azole therapeutic failure (3/4 versus 4/7) or uncleared fungemia (4/6 versus 4/10), but FNS isolates were identified more frequently from patients with previous azole exposure (6/6 versus 3/10; P = 0.011) and immunosuppression (6/6 versus 3/10; P = 0.011). These results reveal that the majority of FNS C. tropicalis isolates show overexpression of CDR1, MDR1, and ERG11 genes, and fungemia develops after azole exposure in patients with immunosuppression.

The increased role of non-albicans species in candidaemia: results from a 3-year surveillance study

Various studies have documented a shift in species distribution in Candida bloodstream infections (BSI), but there are little data from Southeast Asia. This study was performed to determine the species epidemiology and antifungal susceptibilities of Candida species BSI in Singapore. Candida spp. from BSI were collected from a tertiary and secondary referral hospital, and an obstetrics/paediatric hospital over a 3-year period. The most common isolates were Candida albicans (36%), Candida tropicalis (27%), Candida glabrata (16%) and Candida parapsilosis (16%). Candida parapsilosis and C. albicans were predominant in the paediatric hospital, and C. albicans and C. tropicalis predominant in the other two institutions. Candida tropicalis temporarily replaced C. albicans as the predominant strain from BSI in 2006. Overall, 87.3% of Candida isolates were susceptible to fluconazole, and 10.4% classified as susceptible-dose-dependent. Fluconazole resistance was detected in C. tropicalis (3.6%), C. parapsilosis (2.1%) and C. glabrata (4.0%). Candida albicans is the predominant species isolated from BSI in Singapore. However, non-albicans species accounted for nearly two-thirds of all cases of candidaemia and the relative increase in C. tropicalis infections deserves further investigation. Resistance to fluconazole was uncommon.

Species distribution and susceptibility to azole antifungals of Candida bloodstream isolates from eight university hospitals in Korea

PURPOSE

The incidence of Candida bloodstream infections (BSI) has increased over the past two decades. The rank order of occurrence and the susceptibility to antifungals of the various Candida species causing BSI are important factors driving the establishment of empirical treatment protocols; however, very limited multi-institutional data are available on Candida bloodstream isolates in Korea.

MATERIALS AND METHODS

We investigated the susceptibility to azole antifungals and species distribution of 143 Candida bloodstream isolates recovered from eight university hospitals over a six-month period. Minimal inhibitory concentrations (MICs) of fluconazole, itraconazole, and voriconazole for each isolate were determined by the broth microdilution method of the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

The Candida species recovered most frequently from the blood cultures was C. albicans (49%), followed by C. parapsilosis (22%), C. tropicalis (14%), and C. glabrata (11%). The MIC ranges for the Candida isolates were 0.125 to 64 microg/mL for fluconazole, 0.03 to 2 microg/mL for itraconazole, and 0.03 to 1 microg/mL for voriconazole. Overall, resistance to fluconazole was found in only 2% of the Candida isolates (3/143), while the dose-dependent susceptibility was found in 6% (8/143). The resistance and dose-dependent susceptibility of itraconazole were found in 4% (6/143) and 14% (20/143) of the isolates, respectively. All bloodstream isolates were susceptible to voriconazole (MIC, < or = 1 microg/mL).

CONCLUSION

Our findings show that C. albicans is the most common cause of Candida-related BSI, followed by C. parapsilosis, and that the rates of resistance to azole antifungals are still low among bloodstream isolates in Korea.

[Prevention of invasive candidiasis in the critically ill non neutropenic patient]

Prevention of invasive candidiasis (IC) in the setting of critically ill non neutropenic patients should be based on evidenced-based recommendations, namely improved hand hygiene, optimal catheter care, and rational and reduced use of broad-spectrum antibiotics. Concomitant interventions aimed at reducing risk factors are important to decrease IC.

Kodamaea ohmeri isolates from patients in a university hospital: identification, antifungal susceptibility, and pulsed-field gel electrophoresis analysis

Data on clinical isolates of Kodamaea (Pichia) ohmeri, an emerging fungal pathogen, are scarce. Over the past 5 years, we identified yeast isolates from nine patients with fungemia as K. ohmeri by using the API 20C system. Here, we reanalyzed these isolates first by sequencing the internal transcribed spacer 2 (ITS2) regions and then by growing the isolates on CHROMagar Candida medium and subjecting them to pulsed-field gel electrophoresis (PFGE). Based on their ITS2 sequences, six of the nine isolates were confirmed as K. ohmeri, while the others were identified as Candida haemulonii (n = 2) and Candida parapsilosis (n = 1). PFGE karyotyping of the K. ohmeri isolates revealed similar major bands, and their colonies showed a characteristic color change from pink to blue when grown on CHROMagar Candida medium for more than 48 h. For K. ohmeri, the ranges of MICs of fluconazole, voriconazole, caspofungin, and micafungin were 2 to 32 mug/ml, 0.03 to 0.5 mug/ml, 0.125 to 0.25 mug/ml, and 0.03 to 0.06 mug/ml, respectively. Restriction endonuclease analysis of genomic NotI-digested DNA (REAG-N) from isolates from different patients produced unique patterns, suggesting that the fungemia had occurred sporadically. This study determined that ITS2 sequence data, PFGE karyotypes, and CHROMagar Candida chromogenic culture medium are reliable diagnostic tools for identifying K. ohmeri while REAG-N is useful for genotyping the clinical isolates of K. ohmeri.

Factores de riesgo de la candidiasis invasora: estratificación

Risk factors of invasive candidiasis in the setting of non neutropenic critical patients are well known, although currently there is a need to define and validate in prospective multicenter studies risk assessment strategies that would predict accurately the likelihood of invasive candidiasis. The clinical application in order to define which patients should be treated with antifungal prophylaxis and which groups or subgroups of patients should be assessed prospectively during the risk period in order to validate the new diagnostic microbiological indirect techniques for invasive candidiasis and preemptive treatment should be based in these strategies.

Current awareness on yeast

In order to keep subscribers up‐to‐date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly‐published material on yeasts. Each bibliography is divided into 10 sections. 1 Books, Reviews & Symposia; 2 General; 3 Biochemistry; 4 Biotechnology; 5 Cell Biology; 6 Gene Expression; 7 Genetics; 8 Physiology; 9 Medical Mycology; 10 Recombinant DNA Technology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. (4 weeks journals ‐ search completed 10th. Nov. 2004)