Epidemiology 

The epidemiology of Nakaseomyces glabratus is the study of the distribution and determinants of infections caused by this yeast species in human populations. N. glabrata is a common commensal of the human gut flora. Still, it can also cause opportunistic infections and Diabetes in immunocompromised people, such as those with HIV, cancer, organ transplantation, or prolonged use of antibiotics or steroids. N. glabrata infections can affect various sites, such as the vagina, urinary tract, lungs, heart, and bloodstream. 

N. glabrata and is of relevance in nosocomial infections due to its innately high resistance to antifungal agents, especially azoles. Besides its innate tolerance to antifungal drugs, other potential virulence factors contribute to N. glabrata pathogenicity, such as the expression of adhesins genes, the formation of biofilms, and the frequent genome rearrangements.

N. glabrata and belongs to a phylogenetic clade that includes three environmental species and two new human pathogens, N. nivariensis and N. bracarensis. These two species have been recently described as emerging pathogens that can cause similar infections as N. glabrata. However, their epidemiology, biology, identification, pathogenicity, and antifungal resistance still need to be fully understood.

The prevalence of N. glabrata and its related species varies depending on the geographic region, the type of infection, and the patient population. According to some studies, N. glabrata is a relatively more common cause of candidemia in high-income versus low- and middle-income countries. The incidence of N. glabrata infections has increased since the end of the 1990s. It now ranks number two among the Candida species responsible for mucosal and invasive candidiasis in adult patients in Western countries. 

Classification and Structure 

• Kingdom: Fungi 
• Phylum:    Ascomycota 
• Class:        Saccharomycetes 
• Order:      Saccharomycetales 
• Family:     Saccharomycetaceae 
• Genus:       Nakaseomyces 
• Species:   N. glabratus 

 Nakaseomyces glabratus, formerly known as Candida glabrata, is a yeast species. Here are five key points about its structure: 

• Cell Type: Nakaseomyces glabratus is a unicellular, eukaryotic yeast with a rounded or oval cell shape. 
• Cell Wall: It has a cell wall composed of complex carbohydrates, including chitin and glucans. The cell wall offers defense and structural integrity. 
• Cell Membrane: The membrane that envelops the cell is called the cell membrane or plasma membrane and regulates the passage of molecules in and out of the cell. It is a lipid bilayer. 
• Nucleus: Like all eukaryotic cells, Nakaseomyces glabratus contains a nucleus that houses its genetic material, DNA. It is the control center for the cell’s activities. 
• Organelles: Inside the yeast cell, you’ll find various organelles, including mitochondria for energy production, endoplasmic reticulum for protein synthesis, and Golgi apparatus for protein processing and packaging. 

Antigenic Types 

There needs to be more information about the antigenic types of Nakaseomyces glabratus. Antigenic types are usually defined by the presence of specific antigens on the surface of microorganisms, which can elicit an immune response from the host.  

However, Nakaseomyces glabratus does not have a capsule, which is a common source of antigens for many fungi. It also does not produce pseudohyphae or chlamydospores, which are other morphological forms that can affect antigenicity. 

Therefore, it is possible that Nakaseomyces glabratus has a low antigenic diversity and does not have distinct antigenic types. However, this does not mean that it is not immunogenic or virulent. Nakaseomyces glabratus can express a series of adhesin genes, which enable it to adhere to biotic and abiotic surfaces and form biofilms. Biofilms are more resistant to antifungals and host defenses than planktonic cells1. Nakaseomyces glabratus can also undergo genomic rearrangements, which may enhance its fitness and adaptation to stressful conditions. 

Pathogenesis 

The pathogenesis of Nakaseomyces glabratus is the process by which this yeast species causes infections in humans. N. glabrata is a common commensal of the human gut flora. Still, it can also cause opportunistic infections in immunocompromised people, including those undergoing organ transplants, Diabetes, cancer, and HIV, or prolonged use of antibiotics or steroids. N. glabrata infections can affect various sites, such as the vagina, urinary tract, lungs, heart, and bloodstream. 

Some of the factors that contribute to the pathogenesis of N. glabrata are: 

• Resistance to antifungal drugs: N. glabrata is innately resistant to many antifungal agents, especially the azoles. It makes it challenging to treat and eradicate N. glabrata infections. N. glabrata can also develop acquired resistance to other antifungal drugs, such as echinocandins and polyenes. The mechanisms of resistance include mutations in drug target genes, overexpression of drug efflux pumps, and alterations in cell wall composition. 
• Expression of adhesins: N. glabrata can adhere to biotic and abiotic surfaces by expressing a series of adhesin genes. These genes are primarily encoded in the chromosome’s subtelomeric region and are highly regulated by environmental cues. Adhesion is the first step for N. glabrata to colonize and invade host tissues and form biofilms. 
• Formation of biofilms: N. glabrata can form biofilms on medical devices, such as catheters, prosthetic valves, and implants. Complicated microbial colonies encased in an extracellular polymeric matrix are known as biofilms. Biofilms confer increased resistance to antifungal drugs and host immune responses and serve as a source of persistent infection. 
• Genome rearrangements: N. glabrata Rearrangements in the genome are commonly observed and are thought to improve its fitness and adaptation to stressful conditions. Some authors suggest that genome rearrangements are associated with the potential pathogenicity of N. glabrata. Genome rearrangements may affect the expression of genes involved in drug resistance, adhesion, and biofilm formation. 

Host Defenses 

Nakaseomyces glabratus is a yeast species that can cause infections in humans, especially in those who have weakened immune systems. Some of the host defenses that can protect against N. glabrata infections are: 

• The skin and mucosal barriers: These are the first line of defense that prevent the entry of N. glabrata and other microorganisms into the body. The skin and mucosal surfaces have a low pH, secrete antimicrobial peptides and enzymes, and harbor a diverse microbiota that can compete with N. glabrata for nutrients and space. 
• The innate immune system: This is the second line of defense that recognizes and eliminates N. glabrata and other pathogens through various mechanisms, such as phagocytosis, inflammation, and complement activation. The cells of innate immunity, including natural killer cells, neutrophils, macrophages, and dendritic cells, can engulf and kill N. glabrata by producing reactive oxygen species, nitric oxide, and cytokines. The complement system can also opsonize N. glabrata and facilitate its phagocytosis or directly lyse it by forming membrane attack complexes. 
• The adaptive immune system: This is the third line of defense that provides specific and long-lasting immunity against N. glabrata and other antigens. The adaptive immune system consists of two branches: the humoral immunity and the cell-mediated immunity. B cells produce antibodies as part of humoral immunity, which might bind to N. glabrata and neutralize it or enhance its phagocytosis. The cell-mediated immunity involves the activation of T cells that can help B cells produce antibodies or directly kill N. glabrata-infected cells by releasing perforin and granzymes. 

Clinical manifestations 

Nakaseomyces glabratus is a yeast species that can cause infections in humans, especially in those who have weakened immune systems. Some of the clinical manifestations of N. glabrata infections are: 

• Vaginal candidiasis: This is a common infection of the female genital tract caused by the overgrowth of N. glabrata or more species of Candida. Symptoms include itching, burning, irritation, discharge, and pain during sex or urination. 

• Candidemia: This is a severe bloodstream infection. It may have an impact on the body’s different organs and tissues. Symptoms may include fever, chills, low blood pressure, rapid heart rate, confusion, and organ failure. 
• Urinary tract infection: This bladder infection is kidneys or ureters caused by the entry of N. glabrata or other microorganisms into the urinary system. During urination, symptoms could include pain or burning, frequent or urgent need to urinate, blood or pus in the urine, and lower back pain. 
• Pulmonary infection: This is an infection of the lungs or airways caused by the inhalation of N. glabrata or other fungi. Cough, dyspnea, chest discomfort, and fever are possible symptoms of sputum production. 
• Endocarditis: This is an infection of the heart valves or lining caused by the attachment of N. glabrata or other bacteria to the damaged heart tissue. Symptoms may include fever, fatigue, weight loss, night sweats, heart murmur, and embolic complications. 

Diagnosis 

 Diagnosing Nakaseomyces glabratus infections involves various methods, including: 

• Cultures: Effective for vaginal infections, may take days but quick species identification. 

• Chromogenic agar: Special culture medium with white to cream-colored N. glabrata colonies. 
• Microscopy: Examining yeast cell morphology – ovoid to ellipsoidal blastoconidia, no pseudohyphae or chlamydospores. 
• Physiological tests: Measure sugar assimilation patterns to distinguish N. glabrata from other yeasts. 
• Molecular methods: Use DNA/RNA analysis, like PCR fingerprints, D1/D2 domains, ITS sequences, and MALDI ToF MS, to identify N. glabrata and related species. 

Control 

N. glabrata infections can be prevented by following some general measures, such as:

• Keeping your hands clean and practicing proper hygiene. 
• Avoid unnecessary use of antibiotics, steroids, or immunosuppressive drugs that can alter your natural flora and increase your risk of infection. 
• Consuming a healthy diet and probiotics to assist your gut health and immunity. 
• Wear loose-fitting and breathable clothing and underwear to prevent moisture and irritation in the genital area. 
• Changing tampons or pads frequently and avoiding douching or using scented products that can disrupt the vaginal pH and flora. 
• using condoms or dental dams and engaging in safe sexual behavior to prevent transmission of N. glabrata or other sexually transmitted infections. 
• Seeking medical attention if you have symptoms of a fungal infection, such as itching, burning, discharge, pain, fever, or organ dysfunction. 

References 

• Nakaseomyces | Mycology | University of Adelaide 
• Candida Glabrata: What You Need to Know – by Dr. Vibhuti Rana (yeastinfectionadvisor.com)