Prevalence, Species Distribution and Antifungal Susceptibility Profile of Candida Species Isolated from Bloodstream of Critical Care Unit Patients in a Tertiary Care Hospital in Kenya

The upsurge of candidemia in the past years has been an immense encumbrance on public health and the number of deaths caused by candidemia particularly in critical care unit patients is devastating. Candida species harbor a 30% 60% mortality rate and compared to stable people or those with less serious illnesses, this ranges from 60% to 80% of those who are chronically ill patients. Grounded on a recent report from a tertiary care hospital in Kenya showing the emergence of previously unobserved species: Candida auris, this study aimed to determine the prevalence, species distribution, and antifungal susceptibility profile of candidemia in critical care unit patients of the hospital. 378 Critical Care Unit patients were enrolled for the study from January 2019 to January 2020. Positive archived isolates were sub-cultured using Saboraud Dextrose Agar. Candida species were identified utilizing API20C AUX and Vitek-2. Antifungal susceptibility testing was conducted using the Liofilchem MIC Test strip. Out of 378 patients, thirty-one presented a positive culture for Candida species. The prevalence of Candidemia was 8.2% with 9 (29.03%) Candida auris, 8 (25.81%) Candida albicans, 6 (19.35%) Candida parapsilosis, 3 (9.68%) Candida famata, 3 (9.68%) Candida tropicalis, 1 (3.23%) Candida duobushaemolumonii, and 1 (3.23%) Candida lusitaniae. A resistance pattern to Fluconazole was observed among Candida auris and Candida parapsilosis, and resistance to Flucytosine was observed in Candida tropicalis, whereas susceptible MIC values were obtained for the other drugs. There is an increase in candidemia among critical care unit patients in the health facility posing a public health challenge. Moreover, the onset of new species Candida auris which is unprecedented in Kenya warrants enhanced infection control, and the uniform resistance of Candida auris, Candida paHow to cite this paper: Solomon, D.A., Nyerere, A.K., Kanyua, A. and Ngugi, C.W. (2021) Prevalence, Species Distribution and Antifungal Susceptibility Profile of Candida Species Isolated from Bloodstream of Critical Care Unit Patients in a Tertiary Care Hospital in Kenya. Open Journal of Medical Microbiology, 11, 32-46. https://doi.org/10.4236/ojmm.2021.111003 Received: January 30, 2021 Accepted: March 8, 2021 Published: March 11, 2021 Copyright © 2021 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access D. A. Solomon et al. DOI: 10.4236/ojmm.2021.111003 33 Open Journal of Medical Microbiology rapsilosis, and Candida tropicalis towards Fluconazole and Flucytosine necessitate constant drug monitoring for empirical treatment regime. In contrast, the high potency of Echinocandins and Amphotericin-B demonstrate them as the drug of choice.


Introduction
Fungal infections, explicitly Candida species have been the major cause of mortality and morbidity in hospitalized patients and predominantly in the Critical Care Units [1] [2]. Candida species reside inside the host as normal flora and dwell in the oral cavity of healthy human beings, however, in immunocompromised patients, these commensal microorganisms are capable of causing disease [3]. Prominently causing nosocomial infections, Candida spp. rates the fourth in causing all bloodstream infections and third of bloodstream infections in critically ill patients [4]. Worldwide in tertiary care hospitals, those results attribute to mortality rates of 15% ± 35% in adults and 10% ± 15% in neonates [5]. Based on studies done in several hospitalized patients, including intensive care unit patients, candidemia causes mortality of 47% among the patients [6].
In the USA, Candida species are considered as the third or fourth most causative agent of healthcare-acquired infections [5] and lead to a 30% -60% mortality rate of hospitalized patients [6]. These are associated with changes in the individuals' physiology and immunocompromised state which results in severe infections [3]. Several risk factors of the origin of the Candida infections in hospitalized patients could be endogenously brought by the patients themselves or could be from instruments in the hospital. It might also be contributed to contaminations of hospital surroundings or cross-infection from health workers which would attribute to the exogenous cause [5] [7] [8]. Candidemia is frequently seen among those infections, especially with patients in Critical Care Units [5]. Moreover, as a result of these infections, expanded costs in healthcare are incurred, ranging from $35,000 to $68,000 for a single candidemia case in the United States [8].
Patterns of anti-fungal drug resistance by Candida species have been causing stern public health challenges and were encompassed in CDC's 2013 Antibiotic Resistance Threat Report [9] [10]. Critically ill patients undergo invasive treatments and consume several anti-fungal drugs, however, results of anti-fungal resistance have been causing epidemiological unsustainability [11] [12]. Certain Candida strains are progressively resistant to commonly used antifungal drugs.
Based on recent data from CDC, a discernable shift is observed in candidemia occurrences with augmented drug resistance to first-line and second-line anti-fungal drugs such as Azoles and Echinocandins [10]. In the United States, 46,000 hospitalized patients face Candida infections each year, and approximately 30% of those who harbor drug-resistant Candida species are estimated to die during hospitalization [10]. Several reports state that the increase of anti-fungal resistance has been resulting in high mortality and morbidity in critical care patients [2] [13]. This has contributed to many deaths due to Candida infections in the past years [11] [12].
According to literature from Kenya, the significant agent for hospital infections is considered to be Candida albicans [14] [15]. However, Candida auris has recently been observed frequently in a tertiary care hospital in Nairobi, Kenya grounded on several lab reports from ICU and HDU patients. Swift dissemination of this multi-drug resistant species is discerned in different parts of the world [2]. It was first reported in 2009 and since then it has been detected in five continents causing serious hospital-acquired infections [2]. A study conducted in Kenya recorded a drug resistance pattern of Candida albicans and Candida parapsilosis isolates towards fluconazole [14] [16], however, drug susceptibility patterns of the novel species, Candida auris remains unreported up-to-date in Kenya. Therefore, the aim of this study was to determine the prevalence and antifungal susceptibility profile of Candida species among critical care unit patients of the hospital.

Study Area
The study was conducted in a tertiary care hospital in Nairobi, Kenya. The hospital has been officially operational since 9 April 1954 and is located on Argwings Kodhek Road, in the neighborhood of Upper Hill, in Kenya's capital city of Nairobi. The hospital is a high capacity hospital and serves different patients from the whole country [17].

Study Population
The study participants were enrolled from the intensive care unit and highly dependent unit of the hospital. The study population included patients of all age groups who had been requested for blood culture by a physician.

Culture of Isolates
The archived isolates which had positive blood culture underwent a sub culturing method using Saboraud dextrose agar (SDA). Isolates that were stored in glycerol were inoculated in a Petri dish plate with a Saboraud Dextrose media and they were incubated in 37˚C for 24 -48 hours. The appearance of creamy white colonies with soft texture was considered positive for Candida growth.

API 20C AUX and VITEK-2 Tests
A confirmatory test was done for the cultured isolates to identify the specific species using API 20C AUX (Biomerieux, USA). Isolated Candida colonies were inoculated in the API 20C cupules for positive or negative growth check in the 19 assimilation tests [20]. Incubation of the strip was done for 48 and 72 hours in 31˚C, after which the reactions were compared to the first cupule containing negative control. The numbers recorded were interpreted using apiweb TM software (Biomerieux, SA). Isolates that were identified as Candida famata by API 20C AUX (Biomerieux, USA) were confirmed using VITEK-2 version 8.1 (Biomerieux, USA) to differentiate whether they were truly Candida famata or they were misidentified Candida auris or Candida duobushaemolumonii. The test was done following the manufacturer's instructions for VITEK-2 (Biomerieux, USA) [21].

Characteristics of Study Population
A total of 378 patients were tested from January 2019 to January 2020.

Discussion
This study documents the prevalence of candidemia among patients admitted to the critical care unit of a tertiary care hospital in Nairobi, Kenya. The results showed a higher prevalence of 8.2% compared to a study previously conducted in Kenya showing a rate of 5 cases of candidemia per 100,000 patients [15]. The increased candidemia could be attributed to the number of invasive measures taken in hospitalized patients when handling their medical care and the immunocompromised state of the patients also plays a role in the severity of the infection. This ascent in prevalence demonstrates a public health challenge, especially to those who are hospitalized in ICU and HDU and have relatively severe illnesses.
Existing publications of Candida infections in Kenya states that the most frequently isolated Candida species was Candida albicans [14] [16], however, this study highlights the onset of the new species, Candida auris in high prevalence. Candida auris was first isolated in 2009 and recorded cases are portrayed by elevated levels of total mortality [2] [24] [25] and high antifungal resistance rates [26]. Of note, the vast majority of the infections reported involved patients that are critically ill [24] [27]. Furthermore, identification has been difficult by microbiological techniques [2] [28] [29] notwithstanding Candida auris being one of the most prevalent species which increases the risk of misidentification and hence improper treatment. Candida auris's high virulence [30] [31], a profile of multi-drug resistance [32], and rapid outbreak and global propagation marks it as a worldwide threat [2].
The antifungal susceptibility tests performed showed a susceptible profile of all isolates towards Echinocandins and Amphotericin B and Voriconazole. A study conducted in a tertiary care hospital in Italy, however, showed a resistance pattern of Candida albicans towards Voriconazole [33]. Besides, as evidenced in certain reports Candida species are usually susceptible to Amphotericin-B as an antifungal drug [33], and the resistance to Echinocandins is in very low percentages   to Candida albicans and non-albicans except for Candida glabrata [34].

Conclusion
There Mr. James Gachugia for his assistance in editing the manuscript.

Funding
This project is funded by AFRICA-ai-JAPAN Project for materials and reagents used in the research.

Authors Contribution
DAS, AKN, AK, CWN conceived and designed the study. DAS performed laboratory analysis and data analysis. DAS drafted the manuscript. All authors read, reviewed, and approved the final manuscript.

Ethical Approval
Ethical approval was obtained from Jomo Kenyatta University of Agriculture and Technology's Ethics Review Committee and the study site hospital's Ethics Review Committee. No patient was recruited solely for the study, but rather the study was part of the normal patient care process. Access to the data was strictly prohibited to maintain the confidential information of the patient. Patient Identification was done in a way that doesn't disclose the real information of the patient to avoid the leak of patient history.

Data Availability
The data can be provided upon request from the corresponding author.