Candida Parapsilosis: Symptoms, Types, Causes and Treatment

Candida parapsilosis has emerged as a significant fungal pathogen, particularly in healthcare settings and among vulnerable patient groups. Unlike the better-known Candida albicans, C. parapsilosis and its closely related species have unique characteristics that influence disease symptoms, risk factors, and treatment strategies. Understanding these differences is crucial for improving patient outcomes, especially as antifungal resistance continues to rise. In this article, we will explore the symptoms, types, causes, and treatment options for Candida parapsilosis, using the latest research to provide an evidence-based overview.

Symptoms of Candida Parapsilosis

Candida parapsilosis infections can present with a wide range of symptoms, depending on the site of infection and the patient’s underlying health. These symptoms often overlap with those caused by other Candida species but can also have unique features that affect diagnosis and management. Recognizing the subtle differences is essential for timely intervention.

Symptom	Description	Severity	Source
Itching	Mild to moderate pruritus at infection site	Mild	1
Erythema	Redness, especially in vulvovaginal cases	Mild	1
Discharge	Abnormal, less severe than C. albicans cases	Mild	1 14
Fever	Common in bloodstream infections	Moderate/Severe	7 9
Sepsis	Systemic infection signs, especially in ICU	Severe	7 9 10
Endocarditis	Heart infection, often with prosthetics	Severe	7
Visual loss	In endophthalmitis cases	Severe	7

Table 1: Key Symptoms

Overview of Clinical Presentations

The symptoms of Candida parapsilosis vary based on the location and type of infection:

• Mucosal Infections: In vulvovaginal candidiasis (VVC), C. parapsilosis causes itching, erythema, and abnormal vaginal discharge. However, these symptoms are typically milder compared to those caused by C. albicans 1 14.
• Bloodstream Infections (Candidemia): Patients often present with fever, chills, and signs of systemic infection, especially in intensive care units (ICU) or neonatal wards 7 9 10.
• Device-Related Infections: Because C. parapsilosis readily forms biofilms on medical devices, symptoms may include persistent fever and signs of local or systemic infection despite antibiotic therapy 5 7.
• Other Severe Manifestations: In rare cases, C. parapsilosis can cause endocarditis (heart valve infection), endophthalmitis (eye infection), septic arthritis, and peritonitis, primarily in individuals with prosthetic devices or those undergoing invasive procedures 7.

Symptom Severity and Differential Diagnosis

• Comparison with Other Candida Species: The symptoms of VVC caused by C. parapsilosis are generally milder than those induced by C. albicans. Invasive infections, however, can be just as severe and life-threatening as those caused by other Candida species 1 7 9.
• Patient Groups at Risk: Immunocompromised individuals, neonates, and patients with implanted medical devices are at higher risk for severe and systemic manifestations 9 10.
• Diagnosis Challenges: Because the symptoms overlap with other infections, laboratory identification is essential for accurate diagnosis and effective treatment 9.

Types of Candida Parapsilosis

Candida parapsilosis is not a single uniform species; it is now recognized as a complex of closely related species. This reclassification has significant implications for disease management, as each type may differ in virulence, biofilm formation, and antifungal susceptibility.

Type	Features	Clinical Relevance	Source
C. parapsilosis	Most common; strong biofilm former	High prevalence	1 2 3 4 5
C. orthopsilosis	Less frequent; variable biofilm, virulence	Moderate prevalence	1 2 3 4 5 6
C. metapsilosis	Least common; lower adhesion, virulence	Low prevalence	1 2 3 4 5 6

Table 2: Candida Parapsilosis Complex Types

The Candida Parapsilosis Species Complex

• Reclassification: What was once thought to be a single species is now recognized as three genetically distinct species:

  • Candida parapsilosis sensu stricto
  • Candida orthopsilosis
  • Candida metapsilosis 2 4

• Prevalence:

  • C. parapsilosis is the most prevalent, accounting for the majority of clinical isolates in most regions.
  • C. orthopsilosis and C. metapsilosis are less common but are still clinically relevant, especially in some geographic areas 3 4.

Differences in Virulence and Biofilm Formation

• Biofilm Formation: All three species can form biofilms on medical devices, a key factor in persistent and hard-to-treat infections. There are strain-dependent differences, but overall, their ability to form biofilms is similar 5.
• Virulence:
  • C. parapsilosis and C. orthopsilosis have comparable virulence and adhesion properties.
  • C. metapsilosis shows reduced adhesion to human epithelial cells and generally causes milder infections 6.
• Geographic Variations: The distribution of these species varies widely by region, with C. orthopsilosis being more common in South America than Africa, for example 3.

Clinical Implications

• Treatment Considerations: While current antifungal treatments are generally effective against all three, there are subtle differences in susceptibility that may impact therapy choices, especially as resistance emerges 3 4.
• Diagnosis: Accurate species identification is important for epidemiological and clinical reasons, as traditional biochemical tests may not distinguish between complex members 2 3.

Causes of Candida Parapsilosis

Understanding the causes and risk factors for Candida parapsilosis infection is critical for prevention and early intervention. Unlike some other Candida species, C. parapsilosis is particularly adept at thriving in hospital environments and exploiting weaknesses in patient defenses.

Cause	Description	Risk Group	Source
Medical Devices	Biofilm formation on catheters, prostheses	ICU, neonates	5 7 9 15
Immunosuppression	Weakened defenses (e.g., chemotherapy, HIV)	Cancer, transplant	9 10
Parenteral Nutrition	Glucose-rich solutions promote growth	ICU, diabetes	7 15
Hospital Outbreaks	Clonal spread in healthcare settings	All inpatients	7 8 10 11
Vaginal Microbiota	Disruption favors overgrowth	Women	1 14

Table 3: Main Causes and Risk Factors

Hospital-Associated and Device-Related Infections

• Biofilm Formation: A hallmark of C. parapsilosis is its ability to form biofilms on synthetic surfaces, such as intravascular catheters, prosthetic heart valves, and parenteral nutrition lines. These biofilms protect the yeast from both the immune system and antifungal drugs, making infections difficult to eradicate 5 7 15.
• Outbreaks: C. parapsilosis is a well-known cause of hospital outbreaks, especially in neonatal intensive care units (NICUs) and among patients with invasive medical devices. Clonal transmission via healthcare workers’ hands (especially from under fingernails) and contaminated medical equipment is a documented route 7 8 10 11.

Patient-Related Risk Factors

• Immunosuppression: Patients with weakened immune systems, such as those undergoing chemotherapy, organ transplantation, or living with HIV/AIDS, are at higher risk of invasive disease 9 10.
• Parenteral Nutrition and Diabetes: High glucose concentrations, such as those found in parenteral nutrition solutions or in patients with poorly controlled diabetes, enhance the growth and virulence of C. parapsilosis 7 15.
• Disruption of Vaginal Microbiota: In women, disruption of normal vaginal flora (often due to antibiotics or hormonal changes) can predispose to vulvovaginal candidiasis. The protective role of Lactobacillus species is increasingly recognized, and their absence may facilitate C. parapsilosis overgrowth 1 14.

Environmental and Behavioral Factors

• Skin Colonization: C. parapsilosis frequently colonizes human skin, particularly under the fingernails. This trait facilitates transmission in healthcare settings 7.
• Invasive Procedures: Surgeries, insertion of catheters, and other invasive procedures increase the risk of introducing C. parapsilosis into sterile body sites 7 9.

Emerging Resistance as a Cause of Persistent Infection

• Antifungal Resistance: The emergence of fluconazole-resistant and multidrug-resistant strains is an increasing concern. These strains can persist and spread within hospitals, leading to outbreaks that are harder to control and treat 8 10 11 13.

Treatment of Candida Parapsilosis

Effective treatment of Candida parapsilosis infections depends on the site and severity of infection, as well as antifungal susceptibility patterns. Recent years have seen important changes in recommended therapies due to emerging resistance, particularly to azoles.

Treatment	Application	Resistance Issues	Source
Azoles	First-line for mild/moderate	Emerging resistance	1 3 4 8 10 11
Echinocandins	Used for severe/systemic	Variable efficacy	3 12 13
Amphotericin B	Salvage or severe infections	Rare resistance	13
Combined Therapy	Biofilm-associated infections	Potential benefit	15

Table 4: Main Treatment Options

Azole Antifungals

• Fluconazole, Itraconazole, Miconazole: Traditionally effective against C. parapsilosis complex, especially in mucosal and mild bloodstream infections 1 3 4.
• Resistance Trends: Recent global outbreaks of fluconazole-resistant C. parapsilosis have been reported, often associated with specific genetic mutations (e.g., ERG11 Y132F). Resistance is particularly concerning as azoles are the main oral treatment option for candidemia 8 10 11.
• Therapeutic Failure: Resistance is linked to increased mortality and treatment failure, necessitating alternative strategies 8 13.

Echinocandins

• Drugs: Anidulafungin, caspofungin, micafungin.
• Usage: Recommended for severe or invasive infections; generally effective, although C. parapsilosis is inherently less susceptible to echinocandins compared to other Candida species 3 12.
• Clinical Efficacy: Anidulafungin shows good efficacy in candidaemia, with response rates similar to other Candida species 12.
• Resistance: Multidrug-resistant isolates (resistant to both azoles and echinocandins) are emerging and represent a serious therapeutic challenge 10 13.

Polyenes (Amphotericin B)

• Usage: Employed as salvage therapy for severe, resistant, or multidrug-resistant infections. Liposomal amphotericin B (LAMB) is preferred due to better safety 13.
• Efficacy: Remains effective against most C. parapsilosis isolates, including those resistant to azoles and echinocandins 13.

Combination and Adjunctive Therapies

• Combined Therapy: Combining fluconazole with cyclooxygenase inhibitors (e.g., acetylsalicylic acid) may reduce biofilm formation and improve outcomes in biofilm-associated infections 15.
• Probiotics/Postbiotics: Lactobacillus species may reduce C. parapsilosis virulence in the vaginal microbiota, offering potential adjunctive or preventive strategies 14.

Infection Control and Prevention

• Device Removal: Removal or replacement of infected catheters and medical devices is critical for successful treatment 7 9.
• Infection Control: Strict hand hygiene and environmental cleaning are essential to prevent hospital outbreaks, especially in high-risk units 10 11.

Monitoring and Future Directions

• Susceptibility Testing: Routine antifungal susceptibility testing is recommended, particularly in outbreak settings or when treatment failure is suspected 8 10.
• Research Needs: Ongoing studies are needed to better understand resistance mechanisms and develop new antifungal agents 10 13.

Conclusion

Candida parapsilosis is an increasingly important pathogen in both hospital and community settings. Its ability to form biofilms on medical devices, coupled with rising antifungal resistance, makes it a significant challenge for clinicians. A nuanced understanding of its symptoms, the different types within the species complex, causes, and evolving treatment options is essential for improving patient outcomes.

Key Points:

• Symptoms of C. parapsilosis range from mild mucosal irritation to life-threatening invasive disease; vulvovaginal symptoms are typically milder than those of C. albicans, but systemic infections can be severe 1 7 9.
• Types include C. parapsilosis, C. orthopsilosis, and C. metapsilosis, each with distinct prevalence and virulence profiles 2 3 4 5 6.
• Causes center on hospital-acquired transmissions, biofilm formation on medical devices, immunosuppression, and disruption of normal microbiota 5 7 9 10 14.
• Treatment options are evolving due to resistance; while azoles remain frontline for many cases, echinocandins, amphotericin B, combination therapies, and adjunctive probiotic strategies are increasingly important 1 3 4 8 10 12 13 14 15.

Staying informed about emerging resistance patterns, accurate species identification, and individualized therapy is more crucial than ever in the fight against Candida parapsilosis and its complex.