Meningitis caused by Rhodotorula rubra in an human immunodeficiency virus infected patient

New silicate-substituted hydroxyapatite materials doped with silver ions as potential antifungal agents

BACKGROUND

Hydroxyapatites (HAp) are widely used as medical preparations for e.g., bone replacement or teeth implants. Incorporation of various substrates into HAp structures could enhance its biological properties, like biocompatibility or antimicrobial effects. Silver ions possess high antibacterial and antifungal activity and its application as HAp dopant might increase its clinical value.

RESULTS

New silicate-substituted hydroxyapatites (HAp) doped with silver ions were synthesized via hydrothermal methods. The crystal structure of HAp was investigated by using the X-ray powder diffraction. Antifungal activity of silver ion-doped HAp (with 0.7 mol%, 1 mol% and 2 mol% of dopants) was tested against the yeast-like reference and clinical strains of Candida albicans, C. glabrata, C. tropicalis, Rhodotorula rubra, R. mucilaginosa, Cryptococcus neoformans and C. gattii. Spectrophotometric method was used to evaluate antifungal effect of HAp in SD medium. It was shown that already the lowest dopant (0.7 mol% of Ag⁺ ions) significantly reduced fungal growth at the concentration of 100 µg/mL. Increase in the dopant content and the concentration of HAp did not cause further growth inhibition. Moreover, there were some differences at the tolerance level to Ag⁺ ion-doped HAp among tested strains, suggesting strain-specific activity.

CONCLUSIONS

Preformed studies confirm antimicrobial potential of hydroxyapatite doped with silver. New Ag⁺ ion-HAp material could be, after further studies, considered as medical agent with antifungal properties which lower the risk of a surgical-related infections.

Molecular identification and antifungal susceptibility pattern of Candida species isolated from HIV infected Patients with candisiasis

Background and Purpose:

Opportunistic fungal infections have been on a growing trend since the last two decades. Among the opportunistic fungal agents, Candida species, Cryptococcus neoformans, and Aspergillus fumigatus account for most of the life-threatening infections in immunocompromised individuals. Regarding this, the present study aimed to investigate the molecular identification and antifungal susceptibility pattern of Candida species isolated from HIV-infected patients.

Materials and Methods:

This study was conducted on 80 clinical samples collected from HIV-infected patients with suspected candidiasis referring to Tagore Medical College and Hospital, Rathinamangalam and Government Hospital of Thoracic Medicine, in Chennai, India, for 18 months (i.e., May 2016-December 2017). Phenotypic and molecular identification was accomplished using internal transcribed spacer region 1 (ITS1) and ITS4 primers. The antifungal susceptibility pattern of the isolates against four antifungal agents was also determined by both disk diffusion and broth dilution methods.

Results:

In the present study, the prevalence of candidiasis was obtained as 75% (n=60). Candida tropicalis was the predominant identified species. All the emerging species (i.e., Kodamaea ohmeri, Hanseniaspora opuntiae, and C. orthopsilosis) were identified through molecular identification since the phenotypic identification was inconclusive. In terms of the susceptibility pattern, 63.3% and 18.3% of the isolates were resistant to fluconazole and voriconazole, respectively. Candida albicans was also found to be resistant to amphotericin B.

Conclusion:

Molecular assay led to the identification of K. ohmeri, H. opuntiae, and C. orthopsilosis, which were multidrug-resistant. This study highlighted the need for the prompt and timely identification of clinical yeast isolates given the emergence of many rare species and their capability of causing life-threatening infections and outbreaks. In the laboratories where molecular diagnostic methods are not available, alternative services of reference laboratories can be utilized as cost-effective measures. With regard to the growing prevalence of antifungal drug resistance, antifungal susceptibility testing should be made mandatory for effective patient management.

Meningitis Caused by Rhodotorula mucilaginosa in HIV-Infected Patient: A Case Report and Review of the Literature

Rhodotorula species are increasingly being identified as a cause of fungal infection in the central nervous system, especially in patients with compromised immunity. The diagnosis could easily be missed due to low index of suspicion, as cryptococcus meningitis and cerebral toxoplasmosis are more common amongst immunocompromised hosts. To date, there are six cases of Rhodotorula-related meningitis reported, and three are associated with human immunodeficiency virus infection. In this report, a case of a Malaysian male with underlying human immunodeficiency virus infection who developed Rhodotorula mucilaginosa meningitis is presented. High-grade fever and severe headaches were the complaints presented in three previous case reports. India ink and nigrosin stainings were performed in the two previous reports and both revealed positive results. R. mucilaginosa were isolated from the culture of the patient's cerebrospinal fluid in all three previous reports. Predominant lymphocyte infiltration in the cerebrospinal fluid examination was documented in two reports. CD4 counts were above 100/µl in two previously published reports, while another report documented CD4 count as 56/µl. Amphotericin B and itraconazole are identified to be the first line of antifungal used and as the maintenance therapy, respectively. The possibility of relapse cannot be excluded as it was reported in the first report. It was also revealed that the current case has almost similar clinical presentation and therapeutic outcome as compared to the published reports, but some differences in diagnostic details were to be highlighted.

Rhodotorula mucilaginosa associacted meningitis: A subacute entity with high mortality. Case report and review

A fatal case of meningitis due to Rhodotorula mucilaginosa in a 28 year-old HIV-negative male with a history of Hodgkin lymphoma who underwent salvage chemotherapy is presented. Reviewing the literature we identified 13 cases with central nervous system infection due Rhodotorula spp. The disease usually occurs in HIV negative immunosupressed middle-aged males. It takes the form of subacute or chronic meningitis accompanied by fever with an overall mortality of 46.2% despite antifungal therapy.

Identification and antifungal susceptibility of a large collection of yeast strains isolated in Tunisian hospitals

In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used as a rapid method to identify yeasts isolated from patients in Tunisian hospitals. When identification could not be exstablished with this procedure, sequencing of the internal transcribed spacer with 5.8S ribosomal DNA (rDNA) (ITS1-5.8S-ITS2) and D1/D2 domain of large-subunit (LSU rDNA) were employed as a molecular approach for species differentiation. Candida albicans was the dominant species (43.37% of all cases), followed by C. glabrata (16.55%), C. parapsilosis (13.23%), C. tropicalis (11.34%), C. dubliniensis (4.96%), and other species more rarely encountered in human diseases such as C. krusei, C. metapsilosis, C. lusitaniae, C. kefyr, C. palmioleophila, C. guilliermondii, C. intermedia, C. orthopsilosis, and C. utilis. In addition, other yeast species were obtained including Saccharomyces cerevisiae, Debaryomyces hansenii (anamorph known as C. famata), Hanseniaspora opuntiae, Kodamaea ohmeri, Pichia caribbica (anamorph known as C. fermentati), Trichosporon spp. and finally a novel yeast species, C. tunisiensis. The in vitro antifungal activities of fluconazole and voriconazole were determined by the agar disk diffusion test and Etest, while the susceptibility to additional antifungal agents was determined with the Sensititre YeastOne system. Our results showed low incidence of azole resistance in C. albicans (0.54%), C. tropicalis (2.08%) and C. glabrata (4.28%). In addition, caspofungin was active against most isolates of the collection with the exception of two K. ohmeri isolates. This is the first report to describe caspofungin resistant isolates of this yeast.

Epidemiology of Rhodotorula: an emerging pathogen

This is an updated paper focusing on the general epidemiological aspects of Rhodotorula in humans, animals, and the environment. Previously considered nonpathogenic, Rhodotorula species have emerged as opportunistic pathogens that have the ability to colonise and infect susceptible patients. Rhodotorula species are ubiquitous saprophytic yeasts that can be recovered from many environmental sources. Several authors describe the isolation of this fungus from different ecosystems, including sites with unfavourable conditions. Compared to R. mucilaginosa, R. glutinis and R. minuta are less frequently isolated from natural environments. Among the few references to the pathogenicity of Rhodotorula spp. in animals, there are several reports of an outbreak of skin infections in chickens and sea animals and lung infections and otitis in sheep and cattle. Most of the cases of infection due to Rhodotorula in humans were fungemia associated with central venous catheter (CVC) use. The most common underlying diseases included solid and haematologic malignancies in patients who were receiving corticosteroids and cytotoxic drugs, the presence of CVC, and the use of broad-spectrum antibiotics. Unlike fungemia, some of the other localised infections caused by Rhodotorula, including meningeal, skin, ocular, peritoneal, and prosthetic joint infections, are not necessarily linked to the use of CVCs or immunosuppression.

Pathogenic microorganisms carried by migratory birds passing through the territory of the island of Ustica, Sicily (Italy)

Several studies have shown that migratory birds play an important role in the ecology, circulation and dissemination of pathogenic organisms. In October 2006, a health status evaluation was performed on a large population of migratory birds passing through the territory of Ustica (Italy), an island located on the migration route of many species of birds to Africa, and various laboratory tests were conducted. In total, 218 faecal swabs and the internal organs of 21 subjects found dead in nets were collected for bacteriological and virological examination, including avian influenza and Newcastle disease. In addition, 19 pooled fresh faecal samples were collected for mycological examination. The bacteriological analysis produced 183 strains belonging to 28 different species of the Enterobacteriaceae family. In particular, Salmonella bongori, Yersinia enterocolitica and Klebsiella pneumonia strains were isolated. Almost all of the isolates were susceptible to sulphamethoxazole/trimethoprime (99.4%), cefotaxime (98.9%), nalidixic acid (96.7%), chloramphenicol (95.6%), and tetracycline (93.4%). Alternatively, many strains were resistant to ampicillin (42.6%), amoxicillin-clavulanic acid (42.6%), and streptomycin (43.7%). According to reverse transcriptase-polymerase chain reaction analysis, all of the samples were negative for the M gene of avian influenza virus. Moreover, isolation tests conducted on specific pathogen free eggs were negative for avian influenza and Newcastle disease. Several hyphomycetes and yeasts belonging to different genera were present in the specimens, and Cryptococcus neoformans was observed in a pooled faecal sample. Antibiotic resistance in wildlife can be monitored to evaluate the impact of anthropic pressure. Furthermore, migratory birds are potential reservoirs of pathogenic agents; thus, they can be regarded as sentinel species and used as environmental health indicators.

Rhodotorula fungemia: two cases and a brief review

Rhodotorula is emerging as an important cause of nosocomial and opportunistic infections. We present two cases of Rhodotorula mucilaginosa fungemia diagnosed over a period of 3 months at our hospital. The first case was of a pre-term neonate in the neonatal ICU who presented with respiratory failure and sepsis. The second involved an adult female who had been injured in a road traffic accident requiring an operation for a hematoma and was later shifted to the medical ICU. For a new hospital like ours, finding two cases of Rhodotorula fungemia within a span of 3 months prompted us to describe them in this report. These cases emphasize the emerging importance of Rhodotorula mucilaginosa as a pathogen and the importance of identification and MIC testing for all fungal isolates recovered from the blood stream.

Meningitis caused by Rhodotorula mucilaginosa in human immunodeficiency virus seropositive patient

Rhodotorula species may be responsible for systemic infection in immunocompromised patients. Meningitis by Rhodotorula species in human immunodeficiency virus (HIV) infected persons has been reported previously. We report a case of meningitis caused by Rhodotorula mucilaginosa in a 36-year-old HIV seropositive male patient who presented with fever, altered sensorium and features of meningeal irritation i.e. neck rigidity. The Cerebrospinal fluid (CSF) cell counts were high, showing 150 cells/mm(3), with 60% lymphocytes and 40% polymorphs, and protein content of 100 mg%; glucose was 60 mg%. The diagnosis was confirmed by culture on Sabouraud's Dextrose agar. The patient was treated successfully with intensive Amphotericin B (1 mg/kg), for two weeks, followed by oral Itraconazole (400 mg daily), for a period of two months. The patient was started on anti retroviral therapy. He did not show any relapse of the symptoms when the last follow up was done six months after the date of discharge.

Multidrug resistant yeasts in synanthropic wild birds

BACKGROUND

The aim of this study was to investigate the presence of multidrug resistant yeasts in the faeces of synanthropic wild birds from the Bangsar suburb of Kuala Lumpur.

METHODS

Species characterisations of yeast isolates and determinations of antimycotic susceptibility profiles were undertaken using the commercial characterization kit, Integral System Yeasts Plus (Liofilchem, Italy).

RESULTS

Fourteen species of yeasts were detected in the bird faecal samples.Candida albicans was present in 28.89% of bird faecal samples, Candida krusei (13.33%), Candida tropicalis (4.44%), Candida glabrata (4.44%), Candida parapsilosis (2.22%), Candida lambica (2.22%), Candida stellatoidea (2.22%), Candida rugosa (2.22%) and Candida lusitaniae (2.22%). Amongst the non-candidal yeast isolates, Cryptococcus laurentii was present in 6.67% of bird faecal samples, Cryptococcus uniguttulatus (4.44%), Saccharomyces cerevisiae (4.44%), Trichosporon pullulans (2.22%), Trichosporon pullulans/Cryptococcus albidus (8.89%) and Rhodotorula rubra/Rhodotorula glutinis (4.44%). Of the isolated yeasts, 18.1% (or 26/144) were found to be resistant to all 11 antimycotic agents they were tested against i.e. Nystatin, Amphotericin B, Flucytosine, Econazole, Ketoconazole, Clotrimazole, Miconazole, Itraconazole, Voriconazole, Fluconazole 16 and Fluconazole 64. 45.8% (or 66/144) of the bird faecal yeast isolates were resistant to four or more of the 11 antimycotic agents they were tested against.

CONCLUSIONS

This finding is of public health significance as these synanthropic wild birds may be reservoirs for transmission of drug resistant yeast infections to humans.