purpureocillium lilacinum ( thom )   formerly paeciliomyces lilacinus ( thom )   is a non - melanized , ubiquitous , environmental , filamentous mold .
infection caused by this species , now referred to as purpureocilliosis , is sporadic and usually limited to immunosuppressed humans or animals .
p. lilacinum has been most frequently described as the cause of hyalohyphomycosis in humans , a dog , a cat , and reptiles . in humans ,
disease due to p. lilacinum is increasing in importance as the population of immunosuppressed individuals grows and immunosuppressive drugs become more effective and more frequently prescribed .
it is of particular concern in patients with indwelling devices or intraocular lens implants , which contribute to it being considered an emerging fungal pathogen . in rare cases ,
it is diagnosed in humans and animals without underlying immunosuppressive disease or demonstrable evidence of immunosuppression . in order
chelonia , p. lilacinum has been associated with disease in a number of species , including chinese soft - shelled turtles ( trionyx sinens ) , an aldabra tortoise ( dipsochelys dussemieri ) , fly river turtles ( carettochelys insculpta ) , a greek tortoise ( testudo graeca ) , and an ornate slider ( trachemys ornate ) 
 .
susceptibility of sea turtles to p. lilacinum has been represented by a case of disseminated granulomas in a hawksbill sea turtle ( eretmochelys imbricata ) , as the cause of mycotic pneumonia in a group of commercially raised green sea turtles ( chelonia mydas ) , and as the cause of mycosis in loggerhead sea turtles .
a 12 year - old female loggerhead sea turtle ( caretta caretta ) cared for at a public aquarium was found dead in its exhibit after a history of abnormal buoyancy and decreased appetite of several weeks duration , and a necropsy was performed .
the sea turtle had been maintained for 5.5 years in a multi - taxa exhibit tank ( 7.75  m diameter1.2  m deep ) that held 72,000  l of synthetic saltwater at 25 to 26.1  c and 20  ppt salinity .
the most notable macroscopic postmortem finding was that of firm , hemorrhagic lungs with scattered , firm , yellow , well demarcated foci of pneumonia ( fig .
tissue samples of lung and other coelomic viscera obtained at necropsy were fixed by immersion in 10% formalin and submitted to the connecticut veterinary medical diagnostic laboratory ( storrs , ct , usa ) , where they were trimmed and routinely processed for paraffin embedment and histologic sectioning .
swabs of frozen tissue samples of lung were streaked onto sabouraud dextrose agar and inhibitory mold agar with gentamicin ( 0.05 
histopathologic evaluation revealed severe , multifocal and focally extensive , heterophilic and granulomatous pneumonia and pleuritis , with multiple heterophilic granulomas extending into ectatic faveolar spaces and expanding the pleura . in several regions , faveolar septae and pleura
were expanded by infiltrates of degenerate heterophils together with proteinaceous edema and fibrin ( fig .
innumerable , intertwined , non - melanized , septate fungal hyphae were located in granulomas and lining the luminal surfaces of affected faveolar septae .
hyphae were 2.5 to 4  m wide , had parallel walls , and were readily demonstrable using silver stains .
diagnostic fruiting structures , e.g. conidiophores , conidiogenous cells and conidia , were evident in histologic sections of the lung in foci of pneumonia and pleuritis ( fig .
bacteria were present along with hyphae in faveolae in some instances , and bacterial cultures of samples of lung ( performed at a different veterinary diagnostic laboratory ) yielded moderate growth of klebsiella oxytoca and alpha - hemolytic streptococcus , and light growth of proteus mirabilis and enterococcus sp .
there was concurrent ulcerative bacterial cystitis and renal lesions , which included interstitial fibrosis , tubular degeneration and necrosis , and membranous glomerulopathy .
fungal cultures of swabs from the lung grown on sabouraud dextrose agar and inhibitory mold agar with gentamicin ( 0.05 
g / l ) yielded two hyaline molds after 4 days of incubation at 30  c .
these were subsequently referred to the fungus testing laboratory ( university of texas health science center at san antonio , san antonio , tx ) for species identification and were accessioned into their culture collection as isolate numbers uthsc 1030 and 1031 .
they were identified as beauveria bassiana and p. lilacinum , respectively , based upon their macroscopic and microscopic features on potato flakes agar and carnation leaf agar ( prepared in - house ) after 6 days incubation at 25  c .
b. bassiana displayed small , white , granular colonies and produced its smooth , subglobose conidia ( 23  m ) in discrete masses along the hyphae from denticles on a geniculate rachis .
phenotypic features used to identify p. lilacinum included mauve - colored colonies with a pale reverse , finely - roughened conidiophores giving rise to dense clusters of phialidic conidiogenous cells supported on metulae and chains of oval to subglobose conidia borne from these conidiogenous cells .
morphologic features of fruiting structures of the fungus identified in foci of pneumonia and pleuritis were identical to those of the p. lilacinum isolate recovered from the lung , thereby confirming its etiologic role in the pulmonary lesions ( fig .
in this case of mycotic pneumonia and pleuritis , fruiting structures diagnostic for p. lilacinum and comparable to those in culture were recognized in histologic tissue sections in anatomic association with pulmonary lesions .
morphology on fungal culture has previously been combined with morphologic features observed histologically to identify p. lilacinum infections in humans , turtles   and a cat .
identification of p. lilacinum based on its microscopic morphology alone , either in the host or in culture , is difficult since p. lilacinum could be misidentified as either a penicillium or a paecilomyces species , such as p. variotii , due to similarities in reproductive structures .
the color of the colony on a plant - based medium such as potato flakes agar ( pfa ) clearly distinguishes these genera / species , however , which for p. lilacinum , penicillium spp . , and most paecilomyces spp .
would be violet to mauve , some shade of green , or tan to brownish , respectively . because all of the above are common environmental fungi that can be present as laboratory contaminants , the clinical significance of their isolation
this concern is further intensified when the anatomic location of the sample is inherently non - sterile and available to contamination or colonization by an environmental mold , e.g. the skin , mouth or nasal cavity .
histopathologic identification of morphologically compatible fungal structures in lesions can be the key to ascribing significance to isolates from clinical samples and is indispensible in determining whether an isolate represents a contaminant , colonization or bona fide infection .
the phenomenon of fruiting or conidial production in tissue is rare in human fungal infections , where it is mostly seen with chronic cavitary pulmonary aspergillosis ; its occurrence in fungal infections in animals is less well known . in general
, it is rare that histopathologic examination alone can provide the genus and species of a fungus .
this is especially true in cases where hyaline filamentous hyphae are seen in tissue , which makes this case particularly unique and re - emphasizes the need for thorough histopathologic examination toward the most exacting description possible in the context of the anatomic and pathologic features of the case . although no fruiting structures were observed for a beauveria species in the multiple histologic sections examined , this does not rule out the possibility that not - fruiting fungal hyphae of b. bassiana could also have been present .
it is not implausible that an infection by two fungi could have occurred in this turtle .
the occurrence of dual fungal infections in human medicine has been reported to be as high as 20% . like p. lilacinum , b. bassiana is ubiquitous in the environment and capable of being isolated from indoor air ; it too produces hyaline , septate hyphae , which are indistinguishable from those produced by p. lilacinum .
additionally , b. bassiana has been identified as an agent of mycotic pleuritis and pulmonary disease in a turtle , e.g. a captive pond slider ( trachemys scripta ) . in cases of dual fungal infections
, it may be that only the most abundant fungus is recognized ; if the second fungus is isolated in culture but not recognized in tissue section , then histopathologic and culture results will appear discrepant .
pcr was attempted on formalin - fixed , paraffin - embedded tissue from affected areas of lung , but the tissue was unsuitable for fungal pcr testing because dna was not amplifiable from any tissue block using primers and pcr conditions that amplify a fragment of a common housekeeping gene ( data not shown ) .
given these data and the possibility that it could have been an environmental contaminant , the b. bassiana isolate was considered less significant to the origin or progression of the pulmonary lesions in this case .
fungal infection is often associated with poor cellular immunity and can be predisposed by environmental conditions such as overcrowding , high population density , stress , poor water quality and , in the case of cold stunned turtles , a drop in environmental and , hence , body temperature . in this case , however , the turtle was well acclimated to its surroundings , and all water quality parameters were within normal limits .
it is unknown if the concurrent cystitis and renal lesions affected the overall immune status of this turtle .
a complete immunologic evaluation was not performed on this sea turtle ; so , the immune status of this individual before death is open to speculation . on the other hand ,
p. lilacinum has been described in humans and animals without underlying predisposing factors or immunosuppression . in summary , this case demonstrates the infrequently encountered phenomenon of fruiting or conidial production in tissue , and it reiterates the importance of having a histological correlate to fungal culture when environmental fungi are isolated .
even though fungal culture remains the gold standard for diagnosis of purpureocilliosis , since p. lilacinum is a common environmental fungus , the results of culture in the absence of a histologic correlate should be interpreted with care .
poikilotherms represent a broad group of animals of veterinary concern in which environmental factors , specifically temperature , exert significant influence on immunologic processes . as a result
, these animals can be susceptible to infection by opportunistic environmental fungi , some of which may be emerging in their public and veterinary health relevance .
 purpureocillium lilacinum and beauveria bassiana were isolated from lung sampled at necropsy of a 12 year - old female loggerhead sea turtle ( caretta caretta ) that had displayed abnormal buoyancy . 
 histopathologic evaluation revealed pleuritis and pneumonia with non - melanized , septate hyphae and fruiting structures identical to those of p. lilacinum . 
 this case emphasizes the importance of a histological correlate to fungal culture when environmental fungi are isolated and demonstrates the infrequent phenomenon of fruiting or conidial production in tissue . 
Introduction
Case
Discussion
Conflict of interest statement