Phospholipase activity of yeasts from wild birds and possible implications for human disease

Over the last decades, reports on yeast infections in humans have increased especially with respect to immunocompromised individuals. Phospholipases are enzymes which may be associated with pathogenic processes caused by opportunistic yeasts. Phospholipase activity (ph.a.) was investigated in 163 isolates of 13 species of yeasts. A total of 133 isolates were obtained through the screening of a total of 768 cloacae of wild birds (Group I: 182 birds of prey; Group II: 165 passeriformes and Group III: 421 other wild migratory birds), while 30 isolates were recovered from the droppings of birds housed in 32 distinct aviaries (Group IV). Phospholipase production was evaluated and quantified at 2 and 5 day pre-incubation (Pr.t) and incubation times (I.t). Isolates from cloacae (48.1%) and excreta (73.3%) produced ph.a. with the highest values registered after 5 days of I.t. Candida albicans, C. tropicalis, C. glabrata, C. lusitaniae, C. pelliculosa, Cryptococcus albidus, C. laurentii, Trichosporon beigelii, and Saccharomyces cerevisiae displayed the highest ph.a. after 2 days of Pr.t while Candida famata, C. guilliermondii and Cryptococcus neoformans after 5 days of Pr.t. Ph.a. was never found in Rhodotorula rubra isolates recovered from the cloacae of wild birds. Isolates (73.3%) from bird droppings showed a higher ph.a. than those from cloacae thus indicating that wild birds not only act as carriers but may also spread phospholipase-producing yeasts in the environment

Azole susceptibility of Malassezia pachydermatis and Malassezia furfur and tentative epidemiological cut-off values

This study aims to determine the minimal inhibitory concentration (MIC) distribution and the epidemiological cut-off values (ECVs) of Malassezia pachydermatis and Malassezia furfur isolates for fluconazole (FLZ), itraconazole (ITZ), posaconazole (POS), and voriconazole (VOR). A total of 62 M. pachydermatis strains from dogs with dermatitis and 78 M. furfur strains from humans with bloodstream infections (BSI) were tested by a modified broth microdilution Clinical and Laboratory Standards Institute (CLSI) method. ITZ and POS displayed lower MICs than VOR and FLZ, regardless of the Malassezia species. The MIC data for azoles of M. pachydermatis were four two-fold dilutions lower than those of M. furfur. Based on the ECVs, about 94% of Malassezia strains might be categorized within susceptible population for all azoles, except for FLZ, and azole cross-resistance was detected in association with FLZ in M. pachydermatis but not in M. furfur. The study proposes, for the first time, tentative azole ECVs for M. pachydermatis and M. furfur for monitoring the emergence of isolates with decreased susceptibilities and shows that the azole MIC distribution varied according to the Malassezia species tested, thus suggesting the usefulness of determining the susceptibility profile for effective treatment of each species

Malassezia infections in humans and animals: pathophysiology, detection and treatment

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Yeasts isolated from cloacal swabs, feces, and eggs of laying hens

Domestic and wild birds may act as carriers of human pathogenic fungi, although the role of laying hens in spreading yeasts has never been investigated. We evaluated the presence of yeasts in the cloaca (Group I, n = 364), feces (Group II, n = 96), and eggs (Group III, n = 270) of laying hens. The occurrence and the population size of yeasts on the eggshell, as well as in the yolks and albumens, were assessed at the oviposition time and during storage of eggs at 22 ± 1°C and 4 ± 1°C. A statistically higher prevalence and population size of yeasts were recorded in Group I (49.7% and 1.3 × 104 cfu/ml) and II (63.8% and 2.8 × 105 cfu/ml) than in Group III (20.7% and 19.9 cfu/ml). Candida catenulata and Candida albicans were the most frequent species isolated. Candida famata and Trichosporon asteroides were isolated only from the eggshells, whereas Candida catenulata was also isolated from yolks and albumens. During storage, the yeast population size on the shell decreased (from 37.5 to 8.5 cfu/ml) in eggs at 22 ± 1°C and increased (from 4.6 to 35.3 cfu/ml) at 4 ± 1°C. The laying hens harbor potentially pathogenic yeasts in their gastrointestinal tract and are prone to disseminating them in the environment through the feces and eggs. Eggshell contamination might occur during the passage through the cloaca or following deposition whereas yolk and albumen contamination might depend on yeast density on eggshell

Native strains of Beauveria bassiana for the control of Rhipicephalus sanguineus sensu lato

Background Rhipicephalus sanguineus sensu lato ticks are widespread worldwide due to their adaptability to survive under different environmental conditions. They may act as vectors of a wide range of pathogens to humans and animals and their control is based on the use of chemical products on dogs and in the environment. Alternative control strategies, such as the use of entomopathogenic fungi as bio-control agents have also been investigated. The ability of native strains of Beauveria bassiana sensu lato in causing mortality in different tick species (e.g., Amblyomma cajennense and Rhipicephalus microplus) has been demonstrated. However, limited studies have assessed the use of B. bassiana for the control of R. sanguineus s.l. and none of them have employed native strains of this fungus. Here we investigated the pathogenicity of a native strain of B. bassiana (CD1123) against all developmental stages of R. sanguineus s.l.. Methods Batches of eggs, larvae, nymphs and adult ticks were immersed in a suspension of 107 conidia/ml of B. bassiana s.l., isolated from a R. sanguineus s.l. engorged female. All treatment and control groups were observed for 20 days, and the biological parameters (i.e., mortality, hatching, moulting percentage, pre-oviposition period, oviposition period and rate, eggs production efficiency, reproductive efficiency and fitness indexes) were assessed. Results The effect of the B. bassiana strain tested herein on eggs, larvae, nymphs and adults showed a significantly higher mortality than those of the control groups (p < 0.05) at 5 days post-infection. No infected eggs hatched and no infected larvae moulted. Only 15% of infected nymphs moulted into adults. All biological parameters of treated groups differed significantly (p < 0.001) from those of control groups. Conclusions This study demonstrates that a suspension containing 107 conidia/ml of a native B. bassiana strain is highly virulent towards all life-cycle developmental stages of R. sanguineus s.l. and may be of potential interest as a biological control agent against these ticks

Virulence and in vitro antifungal susceptibility of Candida albicans and Candida catenulata from laying hens.

Funder: Università degli Studi di Bari Aldo MoroIn spite of evidence that domestic and wild birds may act as carriers of human pathogenic fungi, data on the role of laying hens as reservoirs of drug resistant and virulent yeasts is lacking. Here, we assess several virulence factors (phospholipase and haemolysin activity) and the antifungal susceptibility profiles of 84 Candida albicans and 17 Candida catenulata strains isolated from cloacae (group A), faeces (group B) and eggs (group C) of laying hens. Of these strains, 95% C. albicans and 23% C. catenulata strains displayed phospholipase and haemolytic activities. For C. albicans, the highest values of phospholipase (Pz = 0.62) and haemolytic activities (Hz = 0.49) were recorded among the strains from group C whilst for C. catenulata (Pz = 0.54; Hz = 0.49) among those from group A. High minimum inhibitory concentration (MIC) values for azoles and amphotericin B (AmB) were recorded irrespective of their sources in all C. albicans strains. A total of 22 C. albicans strains were multidrug resistant, displaying resistance to fluconazole, itraconazole (ITZ), voriconazole (VOR) and posaconazole (POS). All C. catenulata strains from group C were resistant to ITZ, POS, micafungin and anidulafungin and susceptible to AmB. In this study, C. albicans and C. catenulata isolated from the cloacae, faeces and eggs of laying hens produced phospholipase and haemolysin and might be multidrug resistant. In the environment (faeces) or in eggs, C. albicans and C. catenulata strains might acquire pathogenic virulence traits and/or show multidrug resistance profiles. Based on these results, breeding and handling of laying hens and/or eggs may have implications for human and animal health

Virulence and in vitro antifungal susceptibility of Candida albicans and Candida catenulata from laying hens

Funder: Università degli Studi di Bari Aldo MoroAbstract: In spite of evidence that domestic and wild birds may act as carriers of human pathogenic fungi, data on the role of laying hens as reservoirs of drug resistant and virulent yeasts is lacking. Here, we assess several virulence factors (phospholipase and haemolysin activity) and the antifungal susceptibility profiles of 84 Candida albicans and 17 Candida catenulata strains isolated from cloacae (group A), faeces (group B) and eggs (group C) of laying hens. Of these strains, 95% C. albicans and 23% C. catenulata strains displayed phospholipase and haemolytic activities. For C. albicans, the highest values of phospholipase (Pz = 0.62) and haemolytic activities (Hz = 0.49) were recorded among the strains from group C whilst for C. catenulata (Pz = 0.54; Hz = 0.49) among those from group A. High minimum inhibitory concentration (MIC) values for azoles and amphotericin B (AmB) were recorded irrespective of their sources in all C. albicans strains. A total of 22 C. albicans strains were multidrug resistant, displaying resistance to fluconazole, itraconazole (ITZ), voriconazole (VOR) and posaconazole (POS). All C. catenulata strains from group C were resistant to ITZ, POS, micafungin and anidulafungin and susceptible to AmB. In this study, C. albicans and C. catenulata isolated from the cloacae, faeces and eggs of laying hens produced phospholipase and haemolysin and might be multidrug resistant. In the environment (faeces) or in eggs, C. albicans and C. catenulata strains might acquire pathogenic virulence traits and/or show multidrug resistance profiles. Based on these results, breeding and handling of laying hens and/or eggs may have implications for human and animal health