Pneumonia and Pleural Effusion due to Cryptococcus Laurentii in a Clinically Proven Case of AIDS

Abstract

Non-neoformans cryptococci were previously considered to be saprophytes and nonpathogenic to humans. Cryptococcus laurentii is frequently used as a biological means to control fruit rot. Interestingly, C laurentii has recently been reported to be a rare cause of infection in humans. The authors report a case of pulmonary cryptococcosis caused by C laurentii in a diabetic AIDS patient who was on antituberculosis and antiretroviral treatments. The sputum smear revealed capsulated yeast cells that were identified as C laurentii. Repeated pleural fluid culture revealed growth of C laurentii. Both respiratory samples were negative for acid-fast bacilli. Moraxella catarrhalis and Klebsiella pneumoniae were also found in the sputum, but not in the pleural fluid. The patient had a good response to oral fluconazole therapy at 600 mg/day for five weeks and was then discharged. The present article is the first to report on the rare pulmonary involvement of C laurentii in the Indian HIV population. These unusual forms of cryptococci create a diagnostic predicament in the rapid diagnosis of pulmonary cryptococcosis. A high degree of suspicion and improvement of techniques for culture and identification will contribute to the early diagnosis and treatment of unusual fungal infections.

Perspectives on non-neoformanscryptococcal opportunistic infections

“…This survivability may be attributed to its psychrophilic abilities, with an optimal culture temperature of 15.0°C, and poor growth at temperatures >30.0°C [3,6]. Historically, it has been used as a biological pesticide to prevent the decay of fruits and has been demonstrated as a contaminant in the fermentation process of wines and beer [1,7]. Additionally, C. laurentii has been isolated in cases of bovine mastitis [5].…”

“…Transmission of C. laurentii is primarily through inhalation of infective particles by close contact with pigeons or contaminated soil [1–3,6]. In 1998, Johnson et al initially proposed that nosocomial spread was the primary means of transmission.…”

“…However, a literature review demonstrates an increasing prevalence in opportunistic infections [1–3]. The Cryptococcus genus consists of >70 species of anamorphic, basidiomycetous, encapsulated yeast [4].…”

“…C . neoformans , which includes the C. gattii and C. neoformans varieties, remains a common cause of opportunistic infections in immunocompromised states and is classified as an AIDs-defining illness [1]. Non- neoformans Cryptococcus species include C. laurentii , C. albidus , C. curvatus , C. humicolus , and C. uniguttulantus .…”

“…It has been theorized that this increasing incidence may be secondary to a growing number of at-risk or immunocompromised patients, improved awareness, or advancements in laboratory technology [3]. Within the non- neoformans cryptococcal species, C. laurentii and C. albidus account for 80% of pathogenic infections [1–5]. Understanding of the epidemiology and pathogenesis of these species will allow for prompt recognition of non- neoformans cryptococcal infections and improved patient outcomes.…”