Saima Syed¹, Afreenish Amir², Muhammad Waqas Abbas^3*, Saima Ishtiaq¹, Haider Ali¹, Shahid Ahmad Abbasi³

¹MBBS, Postgraduate Trainee, Department of Microbiology, Fauji Foundation Hospital, Rawalpindi, Pakistan

²MBBS, M. Phil, Ph. D, MPH, Technical Officer AMR, National Institutes of Health, Islamabad, Pakistan

³MBBS, FCPS, Consultant Microbiologist, Department of Microbiology, Fauji Foundation Hospital, Rawalpindi, Pakistan

^*Corresponding Author: Muhammad Waqas Abbas, Consultant Microbiologist, Department of Microbiology, Fauji Foundation Hospital, Rawalpindi, Pakistan.

Abstract
Fungal diseases in humans cause high mortality and morbidity, especially in immunocompromised patients. Candida kefyr has rapidly emerged as an invasive pathogen affecting immunocompromised individuals, particularly patients with indwelling central lines, mechanical ventilation, more extended hospital stays, and on hematological malignancies. We present two cases of C. kefyr infections reported from our hospital. This case series highlights the emergence of novel opportunistic fungi, which clinicians and laboratorians need not ignore.

Keywords: Systemic candidiasis, Candida kefyr, immunocompromised

Introduction
Background
The emergence of resistant fungal infections has been a critical healthcare concern. These have resulted in increased morbidity and mortality, especially in immunocompromised patients.[1] Candida spp., although described as asymptomatic commensal, has now evolved as the primary pathogen causing life-threatening invasive infections.[2] It is regarded as a “disease of diseased” in immunocompromised patients.[3]

Candida albicans account for > 50 % of candidemia/ invasive candidiasis cases. Since the last few decades, other Candida species, including C. kefyr, C. auris, C. haemulonii complex members, C. glabrata, C. guilliermondii, C. krusei, C. lusitaniae, C. rugosa are frequently being reported from nosocomial infections with high mortality rates. [4-7] The extensive use of immunosuppressive therapies and broad-spectrum antifungal prophylaxis resulted in this transition. The emergence of inherent or acquired resistance to major antifungal agents is alarming.[8]

Candida kefyr (Kluyveromyces marxianus), previously isolated from dairy products, has also been reported from clinical samples and the hands of healthcare workers.[9] C. kefyr has rapidly emerged as an invasive pathogen affecting immunocompromised individuals, particularly patients with indwelling central lines, mechanical ventilation, more extended hospital stay, and on hematological malignancies.[10] Moreover, recent studies have reported reduced sensitivity of C. kefyr to Amphotericin B, which has raised concern in the healthcare community.[11] The epidemiology of C. kefyr needs to be better understood due to the lack of data available, particularly from our part of the world. This study reports, for the first time, the emergence of C. kefyr strains infecting human patients in Pakistan.

Patient No. 2:
A 62-year-old female presented in the emergency department complaining of oliguria, hematuria, and fever (100oF) for 3 days. She had an acute confusional state and loss of memory. She had a history of CCF with EF < 45 %, DM with left foot amputation, and multiple hospital visits due to recurrent UTIs. Lower limb Doppler suggested monophasic flow in the right dorsal pedis. A plain CT scan brain revealed chronic lacunar infarcts in the right centrum semiovale, left the periventricular region, and pons, with white matter microangiopathic ischemic changes. Laboratory findings revealed deranged RFTs with CrCl <120mg/dl. Urine R/E showed numerous pus cells and red blood cells. Urine culture was inoculated on CLED, and after 48 hrs of incubation at 37oC, there was pure growth of lactose fermenting smooth, shiny colonies confirmed on Gram stain to be Candida spp. The sample was sent to National Reference Laboratory at NIH Islamabad for confirmation up to species level and antifungal susceptibility. Isolate was confirmed by MALDI-TOF mass spectrometry (Biomerieux, France) as C. kefyr. Antifungal susceptibility was tested using Vitek 2. The isolate was found sensitive to Amphotericin B, Voriconazole, and Flucytosine. The patient was put on IV Voriconazole, but due to underlying debilitating illnesses, the patient could not survive.

Discussion
Non-albicans Candida spp., previously considered non-pathogenic, are now being considered responsible for debilitating infections in immunocompromised patients. In this case series, the two patients infected with C. kefyr had underlying chronic illnesses and prolonged drug therapies that affected their immune systems. The first patient had pulmonary tuberculosis, whereas the second had DM and CCF, which increased the risk of fungal infections.   Both the C. kefyr isolates from our hospital were susceptible to Amphotericin B, Voriconazole, and Flucytosine. Other studies, however, reported some resistance to Amphotericin B. [12,13]

C. kefyr is increasingly being isolated from patients with neutropenic leukemia. [14] Recently, C. kefyr was described as a pathogen causing invasive fungal enteritis in a patient with an underlying hematological disease following bone marrow transplantation.10 Sendid et al. reported a twofold detection rate of C. kefyr isolates from adult patients in onomatology wards compared to patients in other wards (4.8 % vs. 1.9 %).[15] 

Conclusion
Among non-albicans Candida spp., C. kefyr has emerged as a significant pathogen in nosocomial infections. This study reports the emergence of C. kefyr strains from Pakistan for the first time. It is highly recommended that its isolation from the clinical specimens should no longer be ignored or considered a contaminant. An early diagnosis and prompt treatment may improve the morbidity and mortality rates.

List of Abbreviations

COPD - chronic obstructive pulmonary disease

ATT - anti-tuberculosis therapy

LTOT - long-term oxygen therapy

MRI – Magnetic resonance imaging

C/S – Culture and sensitivity

SDA - Sabouraud-dextrose agar

NRL - National Reference Laboratory

NIH - National Institute of Health

MALDI-TOF – Matrix Assisted Laser Desorption Ionization – Time Of Flight

CCF - Congestive cardiac failure

EF – Ejection fraction

DM - diabetes mellitus

UTI - Urinary tract infection

CT – Computed tomography

CrCl – Creatinine clearance

RFT - Renal function test

R/E – Routine examination

CLED - Cysteine lactose electrolyte deficient agar

IV – Intravenous

Declarations
Ethics approval: Approval to conduct this study was acquired from Ethical Review Committee, Fauji Foundation Hospital, Rawalpindi.

Consent for publication: Not applicable.

Availability of data and materials: Not applicable.

Competing interest: None to declare.

Funding: Our research did not receive grants from any internal or external funding agencies.

Author’s contribution: SS wrote the manuscript and made substantial contribution to the concept and design of the article, AA provided advanced laboratory diagnostic techniques for the identification of isolates, HA and SI contributed in analysis and interpretation of data, MWA and SAA revised the manuscript critically and approved the version to be published.

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