Candida lusitaniae

When vaginal itching, burning or discharge persists after treatment, identifying the yeast can help investigate the cause. Candida lusitaniae is an uncommon possibility. Finding it still requires interpretation: yeast can be present while another condition causes your symptoms. ACOG guidance.

What the Swab Picks Up

C. lusitaniae is a yeast that can inhabit the vaginal lining and occasionally cause infection. Some laboratories and papers call it Clavispora lusitaniae. This result concerns its presence in a vaginal sample; findings from blood, urine or stool describe different sites and need separate interpretation. Vaginal culture study.

The catalog reports this test in x10^5 CFU/g, or multiples of 100,000 colony-forming units per gram. In a culture, colony-forming units estimate organisms capable of growing into colonies. The catalog does not specify this test's method, so its units alone do not establish that the laboratory cultured live yeast or how it calculated the reported amount.

Identifying a yeast species has an established role in evaluating complicated vaginal infections. Using this species' numerical abundance as a measure of vaginal health remains exploratory. The studies below do not establish a diagnostic threshold in this test's units or an amount to target for prevention. A larger reported amount alone cannot establish that the yeast is causing disease. CDC guidance.

How Uncommon It Is

C. lusitaniae usually represents a small share of vaginal yeast samples, although estimates differ between locations and study populations. A Greek clinic study reported it in about half a percent of yeast isolates. Greek study.

These counts come from the studies by Anh and colleagues, Weldegebreal and colleagues, and Consuegra-Asprilla and colleagues. They describe species identification after vaginal culture, not validation of this test's numerical result. Because the populations and locations differed, the higher Colombian proportion does not by itself establish that recurrent infection specifically favors this species.

Recurrent Infections and Drug Resistance

Candida albicans causes most vaginal yeast infections, including most recurrent infections. Non-albicans species as a group are overrepresented in recurrent and hard-to-treat infections, though, making up as much as about 40% of recurrent cases in some clinic series. They deserve attention when treatment fails, but identifying C. lusitaniae does not by itself establish resistance to the drugs used for vaginal infection. CDC guidance.

The two C. lusitaniae samples in the eastern Ethiopian study were reported susceptible to every antifungal tested. That small finding cannot predict your response, but it shows why this species should not automatically be described as resistant to vaginal yeast treatments. Laboratory susceptibility testing measures how a cultured yeast responds to a drug under laboratory conditions. Its results can inform treatment without guaranteeing that symptoms will resolve. Ethiopian study; ISSVD guidance.

The Colombian study also found reduced yeast-killing activity and reduced multiplication of certain immune cells in women with recurrent candidiasis. Those experiments used cells collected from blood and challenged them with C. albicans. They were not experiments on vaginal C. lusitaniae, and they do not establish that a positive vaginal result reflects an immune deficiency. Colombian study.

Carriage and Vaginal Bacteria

Carriage means yeast is present without causing disease. Even when you have symptoms and a positive culture, the yeast may be incidental. In a specialist clinic study of women with symptoms and non-albicans Candida, yeast appeared responsible for symptoms in about half of cases. That finding concerned several species together. Specialist clinic study.

Vaginal bacteria and yeast also coexist in ways that are more complicated than a simple loss of protective bacteria. Among 255 women in one study, Candida detection was associated with nearly three times the odds in communities dominated by Lactobacillus iners compared with those dominated by Lactobacillus crispatus. This was an association with Candida as a group, not a result specific to C. lusitaniae. Vaginal microbiome study.

Laboratory experiments in that study found that acid produced by L. crispatus inhibited C. albicans growth. A separate Kenyan cohort associated the presence of lactobacilli with symptomatic candidiasis. These findings do not establish a bacterial profile that diagnoses or prevents C. lusitaniae infection. Laboratory experiments; Kenyan cohort.

Pregnancy

A review of 15 studies involving more than 33,000 women found no clear association between vaginal Candida carriage without symptoms and preterm birth, babies born small for their gestational age, or deaths around birth. The analysis concerned Candida as a group. It did not establish pregnancy risks specific to C. lusitaniae. Pregnancy meta-analysis.

Infections Beyond the Vagina

C. lusitaniae can cause bloodstream infections in people with serious underlying illness. In one case series, all 18 affected children had severe underlying disease. Those blood-culture findings describe a different clinical setting; a positive vaginal swab does not show that yeast has entered your bloodstream. Pediatric bloodstream-infection study.

This is also where the species' best-known resistance matters. C. lusitaniae is frequently resistant to amphotericin B, sometimes developing that resistance quickly during treatment, and some strains switch back and forth between susceptible and resistant states. Amphotericin B is an intravenous drug for serious invasive fungal infections. It is not a vaginal treatment, so this trait does not change how a vaginal infection is managed.

When Results Can Be Misleading

• Test coverage: some molecular vaginitis panels omit this species, while expanded panels can include it. A negative result only addresses the organisms that the particular assay detects. Expanded molecular panel specifications.
• Microscopy: an office examination of vaginal fluid can miss yeast that culture detects. A negative smear therefore does not exclude candidiasis when symptoms remain suggestive. CDC diagnostic guidance.
• Species identification: unusual yeasts can be misidentified by basic laboratory methods. In the Ethiopian study, more advanced identification corrected some initial classifications of C. lusitaniae. An unexpected result may need confirmation by a laboratory experienced with uncommon yeasts. Ethiopian study.
• Recent antifungals: treatment can suppress yeast growth and make culture or microscopy negative despite recent infection. How treatment affects this catalog result depends on its unspecified method. Melbourne Sexual Health Centre guidance.
• Different methods and laboratories: culture counts and molecular measurements are not interchangeable. Collection and transport also matter. Even a change measured by the same assay has no validated C. lusitaniae threshold for symptom improvement or treatment success.