Risk factors for Candida non-albicans candidemia

Increased prevalence of fungemia in Medina, Saudi Arabia

Background

The prevalence of fungal infection is increasing globally due to an increase in the immunocompromised and aging population. We investigated epidemiological changes in fungemia in one of the major centers in Medina over seven years period with 87,447 admissions.

Methods

Retrospective search of records for causative agents of fungemia in inpatients at King Fahad Hospital (KFH) in 2013-2019. Fungal-positive blood cultures, demographic, and treatment data were extracted.

Results

A total of 331 fungemia episodes proven by blood culture were identified in 46 patients. The annual prevalence of fungemia increased from 0.072 in 2013 to 1.546 patients per 1,000 in 2019. The mean age of fungemia episodes was 56 years, and 62% of episodes occurred in females. Samples from central blood incubated aerobically yielded the highest fungemia rate, accounting for 55% (n = 182). Among yeast species, Candida parapsilosis was responsible for the highest number of episodes 37% (n = 122), followed by Candida glabrata (32%; n = 107), Candid albicans (29%; n = 94), and Cryptococcus neoformans (1%; n = 4). Among molds, Lichtheimia (Absidia) species was the most common (1%; n = 3). Yeast-like fungi Trichosporion mucoides accounted for (0.003% n = 1). The use of antifungal treatment has increased (96%) over the years (2013-2019). An increase in resistance rate of 2% was found in C. albicans and C. glabrata. The most prevalent comorbidity was renal disease (24.2%).

Conclusions

C. parapsilosis was the leading cause of fungemia. The association of renal disease with increased candidemia was alarming. This study is a fundamental resource to establish management policies for fungal infection in the region.

An alarming rise of non-albicans Candida species and uncommon yeasts in the clinical samples; a combination of various molecular techniques for identification of etiologic agents

OBJECTIVE

Yeasts are unicellular microorganisms may cause systemic infection in immunocompromised patients. The aim of this study was to identify yeast strains isolated from clinical specimens using molecular techniques.

RESULTS

A total of 202 yeast strains isolated from 341 clinical samples between February 2017 and May 2019. All clinical isolates were identified using phenotypic and molecular tests including PCR-RFLP, duplex-PCR, multiplex-PCR, and PCR-sequencing. The most yeast fungal isolates were obtained from urine (66.8%), nail (9.4%), skin lesion (7.9%), bronchoalveolar lavage (5.9%), and blood (3.9%). One hundred and twenty-one Candida species were identified as non-albicans versus 76 Candida albicans. Trichosporon asahii, and Pichia terricola were uncommon non-Candida yeasts isolated from urine samples. For the first time, we isolated P. terricola as etiological agent of urinary tract infection in a pregnant female. Since Candida species show different levels of resistance to antifungal agents, precise identification of clinical isolates is critical for better treatment of infection.

Invasive candidiasis in intensive care units in China: Risk factors and prognoses of Candida albicans and non-albicans Candida infections

BACKGROUND

To investigate the risk factors and prognoses of patients with invasive Candida albicans and non-albicans Candida (NAC) infection in intensive care units (ICUs) in China.

METHODS

Between November 2009 and April 2011, we performed a prospective study of critically ill patients with invasive Candida infection from 67 ICUs across China to compare the risk factors and mortality between patients with C albicans and NAC infection.

RESULTS

There were 306 patients with proven invasive Candida; 244 cases (a total 389 Candida isolates) were sent to laboratory for strain identification (C albicans, 40.1%; NAC, 59.9%). More patients admitted for surgery or trauma had NAC infection than C albicans infection. C albicans infection was more common in patients with subclavian vein catheters or peritoneal drainage tubes. Compared with patients with C albicans infection, patients with NAC infection had longer antifungal therapy (P < .001), longer ICU (P = .004) or hospital stay (P = .002), and slightly higher mortality (38.4% vs 29.6%), but the difference was not significant (P = .17).

CONCLUSIONS

C albicans remains the most common pathogen in candidiasis in critical care patients. However, the number of NAC infections exceeded C albicans infections. Compared with patients with C albicans infection, patients with NAC infection had heavier disease burdens.

Biofilm formation in clinical Candida isolates and its association with virulence

Biofilm formation, an important virulence trait of Candida species was measured in 107 Candida isolates from 32 candidemic patients by XTT [2,3-bis (2-methoxy-4nitro-5-sulfo-phenyl)-2H-tetra-zolium-5-carboxanilide] activity and compared to biofilm formation of Candida isolates from oropharyngeal lesions of 19 AIDS patients. Biofilm formation by XTT varied among species and C. albicans; C. lusitaniae and C. krusei produced more biofilm than the other Candida species. C. tropicalis was the most dominant species isolated from blood followed by C. albicans, and other non-albicans species whereas only C. albicans was recovered from oral lesions. Importantly, though Biofilm formation was variable within a species it was stable in sequential isolates during chronic infection. Sequential isolates exhibited identical Karyotype pattern or RAPD patterns unless patients were co-infected with more than one strain. High biofilm formation was associated with slow growth rate but not with adherence. Murine infection studies demonstrated that, degree of in-vitro biofilm formation was associated with virulence in mice, as mice infected both with no and low biofilm formers survived longer than mice infected with high biofilm former C. albicans (p< or =0.001). We conclude that biofilm formation is a stable but strain specific characteristic that can greatly vary among C. albicans and non-albicans strains, and plays an important role in persistence of infection.