Many globally isolated AD hybrid strains of Cryptococcus neoformans originated in Africa

Interspecific and intervarietal hybridization may contribute to the biological diversity of fungal populations. Cryptococcus neoformans is a pathogenic yeast and the most common fungal cause of meningitis in patients with AIDS. Most patients are infected with either of the two varieties of C. neoformans, designated as serotype A (C. neoformans var. grubii) or serotype D (C. neoformans var. neoformans). In addition, serotype AD strains, which are hybrids of these two varieties, are commonly isolated from clinical and environmental samples. While most isolates of serotype A and serotype D are haploid, AD strains are diploid or aneuploid, and contain two sets of chromosomes and two mating type alleles, MATa and MATα, one from each of the serotypes. The global population of serotype A is dominated by isolates with the MATα mating type (Aα); however, about half of the globally analyzed AD strains possess the extremely rare serotype A MATa allele (Aa). We previously described an unusual population of serotype A in Botswana, in which 25% of the strains contain the rare MATa allele. Here we utilized two methods, phylogenetic analysis of three genes and genotyping by scoring amplified fragment length polymorphisms, and discovered that AD hybrid strains possessing the rare serotype A MATa allele (genotype AaDα) cluster with isolates of serotype A from Botswana, whereas AD hybrids that possess the MATα serotype A allele (AαDa and AαDα) cluster with cosmopolitan isolates of serotype A. We also determined that AD hybrid strains are more resistant to UV irradiation than haploid serotype A strains from Botswana. These findings support two hypotheses: (i) AaDα strains originated in sub-Saharan Africa from a cross between strains of serotypes A and D; and (ii) this fusion produced hybrid strains with increased fitness, enabling the Botswanan serotype A MATa genome, which is otherwise geographically restricted, to survive, emigrate, and propagate throughout the world.

Hybridization between individuals of different species or varieties is common among fungi. However, the impact of hybridization on the evolution of pathogenic fungi is unresolved. Several hybrids of phytopathogenic fungi exhibit expanded host ranges. To our knowledge, this report is the first description of increased hybrid fitness (hybrid vigor) in a human pathogen, Cryptococcus neoformans, the most prevalent cause of fungal meningitis. We demonstrate that diploid hybrid strains are common among both environmental and clinical isolates of two varieties, represented by serotypes A and D. We determined that many globally isolated AD hybrid strains originated in sub-Saharan Africa and have increased resistance to ultraviolet radiation. We hypothesize that hybrid strains have increased fitness, which enabled them to emigrate from Africa and spread globally.

Scedosporium apiospermum infection after near-drowning

Scedosporium apiospermum and its teleomorph (sexual form) Pseudallescheria boydii are ubiquitous saprophytic fungi, which under specific conditions, such as near-drowning, may cause therapy-refractory and life-threatening infections. We reviewed 22 cases (eight children and 14 adults) of S. apiospermum infection after near-drowning reported in the literature including an additional paediatric case from our institution. Scedosporiosis after near-drowning was associated with high mortality (16/23, 70%) even in immunocompetent hosts. It affected mainly young (mean age 24 years) and immunocompetent (83% with no apparent immune defect) males (male to female ratio 2.5 : 1). Scedosporiosis after near-drowning was a slow progressive disease (mean survival time 87 days) involving virtually all body organs. However, central nervous system (CNS) dissemination predominated (21/23, 91%) presenting mainly as multiple brain abscesses (15/23, 65%). All 23 patients showed preceding clinical and/or radiological evidence of lung disease indicating the mode of invasion. Diagnosis was delayed (median time to diagnosis 28 days) and was made by culture (16/23, 69.5%) or culture and tissue examination (7/23, 30.5%). The majority of the patients (20/23, 87%) received antifungal treatment and underwent neurosurgery. While the optimal treatment remains undefined, the most recent reports indicated voriconazole as a potentially effective option. Better knowledge of scedosporiosis after near-drowning could lead to improved intervention and ultimately to more favourable outcome.

Cutaneous and meningeal sporotrichosis in a HIV patient

A male patient with HIV and past history of tuberculosis and suspected neurotoxoplasmosis was admitted to the hospital with vomiting and small nodules through all his body. Few of the nodules were found forming chains of enlarged lymphatic vessels, especially on lesions located on the limbs. Some of the nodules were ulcerated with a serosanguineous discharge. Collected samples from ulcerated and the nodular lesions showed the presence of Sporothrix schenckii in culture. Although all hemocultures were negative, a spinal fluid collected from this patient and cultures from the cutaneous lesions were both positive for S. schenckii. The patient showed improvement after treatment with Amphotericin B. Sadly, he later died of complications not related to the S. schenckii infection. This case of disseminated sporotrichosis is a remainder that in patients with immunological disorders exotic forms of this fungal clinical entity could be expected.

Efficacy of amphotericin B lipid complex in a rabbit model of coccidioidal meningitis

OBJECTIVES

We compared the efficacy of treatments in a rabbit model of coccidioidal meningitis (CM).

METHODS

Rabbits were infected intracisternally with Coccidioides immitis and treated with intravenous amphotericin B lipid complex (ABLC), deoxycholate amphotericin B (dAMB), oral fluconazole or diluent [sterile 5% dextrose in water (D5W)]. Survival and cfu in brain, spinal cord and CSF were determined and histology studied. Amphotericin B (AMB) concentrations in serum, CSF and tissue were determined by bioassay.

RESULTS

Fluconazole-treated rabbits and controls lost weight and had decreased mobility. All treatments prolonged survival (P = 0.005) and reduced cfu in brain and spinal cord (P <or= 0.008); ABLC or dAMB significantly reduced cfu in CNS tissues compared with fluconazole (all P <or= 0.02). ABLC cleared cfu from CSF faster than dAMB or fluconazole. Histologically, 9/9, 7/8 and 0/24 of the D5W, fluconazole and amphotericin groups, respectively, had severe meningitis. Serum AMB was higher after ABLC at 15 mg/kg than after dAMB (P <or= 0.02).

CONCLUSIONS

Intravenous ABLC was efficacious and could be a treatment option for CM.

Aspergillus meningitis and discitis from low-back procedures in an immunocompetent patient

We present a case of an immunocompetent patient who developed Aspergillus meningitis, subsequent to discitis, presumed to be from an epidural steroid injection. Magnetic resonance imaging (MRI) of the lumbar spine confirmed the diagnosis of discitis. Fluoroscopic-guided aspiration of the disc showed growth of Aspergillus fumigatus. MRI of the brain revealed involvement of the right third cranial nerve. Repeat MRIs demonstrated multiple leptomeningeal masses consistent with granulomatous meningitis. Meningitis is a rare complication of discitis, discogram, or epidural steroid injection. Aspergillus usually only infects immunocompromised patients, but rarely can affect immunocompetent patients.

Fungal neuroinfections: rare disease but unacceptably high mortality

Within last 25 years we have observed 20 cases of fungal meningitis and/or cerebral abscesses. Commonest etiologic agens was Candida spp. (C. albicans 9 of 20). Molds were responsible for 4 cases of brain abscess. Mortality was 50% what seems to be very high. Extremely high mortality is caused by delayed onset of therapy, severe underlying disease and multiresistant fungal organisms such as Mucorales, Fusarium solani and Aureobasidium.

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

Rhodotorula spp. are common saprophytes but may be responsible for systemic infections in immunocompromised patients. Meningitis caused by Rhodotorula spp. in human immunodeficiency virus (HIV) infected patients has been reported only rarely. We present a case of meningitis caused by Rhodotorula rubra in HIV infected patient. The presumptive diagnosis of cryptococcal meningitis was made on the basis of India ink preparation, Gram staining and latex agglutination test (LAT) for cryptococcal antigen. The final diagnosis was confirmed by isolation of Rhodotorula rubra from cerebrospinal fluid on culture. LAT was considered false positive. Amphotericin B and 5-fluorocytosine were administered but the patient succumbed to his illness.

Comparison of itraconazole and fluconazole treatments in a murine model of coccidioidal meningitis

Coccidioidal meningitis (CM) is a devastating disease that requires long-term therapy and for which there is little hope of a cure. A model was used to compare the efficacies of itraconazole and fluconazole. CD-1 mice were infected intrathecally with 30 to 36 viable arthroconidia of Coccidioides. Oral therapy with cyclodextrin (control) or itraconazole or fluconazole at 10, 25, or 50 mg/kg of body weight twice daily (BID) was given for 12 days, from day 3 of infection. Treatment with both antifungals at all doses prolonged survival compared with that of the control treatment (P < 0.01 to 0.0001). At 50 mg/kg, itraconazole and fluconazole were equivalent, whereas itraconazole at 10 or 25 mg/kg prolonged survival compared to that achieved with fluconazole at these dosages (P < 0.05 and 0.01, respectively). Early histologic analysis (10 days of treatment) with 50 mg/kg BID itraconazole or fluconazole showed suppression of CM in all five animals per group; in quantitative cultures, three of three animals from each group had no detectable infection in the brain, spinal cord, or a site of secondary infection, the lungs. In contrast, four of seven controls showed mild to severe meningitis, with arteritis detected in three animals. In a short-term organ clearance study, 5 days of treatment with 10 or 50 mg/kg BID itraconazole or fluconazole reduced the tissue burdens in the brain and spinal cord compared to the tissue burdens in the controls (P < 0.02 to 0.0003). Fluconazole at 10 mg/kg did not reduce the fungal burden in secondary sites, the lungs and kidneys, whereas this itraconazole dose was more effective in clearing the fungi from both organs (P < 0.05 and P < 0.001, respectively). At 50 mg/kg, itraconazole and fluconazole were equivalent in clearing the fungi from the brain and kidney, but itraconazole was superior to fluconazole in clearing the fungi from the spinal cord and lungs (P < 0.05). Thus, both itraconazole and fluconazole were effective at controlling CM, but neither eliminated Coccidioides from tissues. Overall, itraconazole was more efficacious on an mg/kg basis; at high doses they were similarly effective.

Candida meningitis in a suspected immunosuppressive patient--a case report

Meningitis due to fungal agents represents an AIDS-defining event and occurs typically with very low CD4+ lymphocyte count. Candida meningitis is still a rare clinical condition, although it is becoming frequently reported in the background of immune suppressive states such as: drug addicts, cancer patients, organ transplant recipients and HIV/AIDS patients. In this report we highlight a case of candida meningitis, in a 25- year old female patient. She presented with vulva swelling, vaginal discharge and fever, with rapid progression to tonic-clonic convulsions and loss of consciousness. She fully recovered after treatment with fluconazole.

Disseminated Scedosporium apiospermum Infection in a Cystic Fibrosis Patient After Double-lung Transplantation

Scedosporium apiospermum is a saprophytic ubiquitous filamentous fungus. It can cause a wide spectrum of diseases, from localized to invasive infections. S apiospermum has been described as one of the major fungal agents of chronic colonization of airways in cystic fibrosis (CF) patients. Invasive infections due to S apiospermum are only rarely reported in CF after lung transplantation. A 26-year-old woman with CF and chronic bronchial colonization by S apiospermum developed bilateral chorioretinitis and subcutaneous nodules 4 weeks after double-lung transplantation (LTx). Isolates of S apiospermum from sputum samples before and after LTx and from vitreal fluid were typed by random amplification of polymorphic DNA (RAPD). The patient was treated with voriconazole (VRC). The patient improved with VRC given orally for 6 months. Two days after VRC discontinuation, she developed sub-acute meningitis (isolation of S apiospermum from the cerebrospinal fluid). She was again given VRC, but died 23 days later from uncontrolled fungal infection. Molecular typing of clinical isolates of S apiospermum performed by RAPD demonstrated that all isolates belonged to the same genotype. S apiospermum is a frequent, but late colonizing fungal agent in CF patients. In the case of LTx, these patients can develop invasive infection due to the colonizing strain, as confirmed by molecular typing.

Nosocomial meningitis in a university hospital between 1993 and 2002

The aim of this study was to establish the relationship between nosocomial meningitis (NM) and surgical interventions, type of pathogens and other hospital infections (HIs). Fifty-one patients diagnosed with NM, according to the criteria of the Centers for Disease Control and Prevention, in the Neurosurgery Department of Ibn-i Sina Hospital of Ankara University between 1993 and 2002 were evaluated retrospectively. All individuals with NM were hospitalized in the intensive care unit. Third-generation cephalosporins were used for surgical prophylaxis and broad-spectrum antibiotics were used for treatment. NM occurred in 0.34% of all admissions and accounted for 0.53% of all HIs. Fourteen cases (28%) had at least one concurrent HI, mainly originating from surgical wounds and related secondary bacteraemia. Four cases had NM following surgical site infection with the same causative agent and three cases had bacteraemia. All the individuals had surgical interventions and 26 (51%) had operations concerning ventriculoperitoneal shunt. A positive microbiological cause was found in the cerebrospinal fluid of 49 patients, with 16 cases having a polymicrobial cause. Of all 67 micro-organisms isolated, 41 (61%) were Gram-negative bacilli, 23 (34%) were Gram-positive cocci and the remaining three (5%) were Candida spp. Staphylococci were the most common pathogens (30%), followed by non-fermentative Gram-negative bacilli (22%).

Disseminated Sporothix schenckii in a patient with AIDS

Sporothrix schenckii is a widespread dimorphic fungus which can cause cutaneous infection following local implantation. Disseminated sporotrichosis may occur in immunodeficient individuals but meningitis remains a rare complication. Diagnosis is usually difficult, requiring isolation of the organism from the CSF or skin so appropriate treatment can be promptly initiated. We present the first case of S. schenckii meningitis reported in the UK in a patient with AIDS. He presented with insidious features of meningoencephalitis, hydrocephalus and multiple cutaneous lesions and failed to respond to therapy.

[Candida albicans meningo-encephalo-myelo-radiculitis at an addict]

Beside immunodepression induced by the human immunodeficiency virus, fungal infections of the central nervous system are extremely rare in heroin-addict patients. We report here a case of meningo-encephalitis with myelo-radicular lesions in a 25-year-old intravenous heroin addict but non-HIV patient, who was admitted for an acute confusion associated with gait disorders. The diagnosis of Candida albicans meningo-encephalo-myelo-radiculitis was established by magnetic resonance imagery and mycological and serological examinations of cerebrospinal fluid. The infection was cured with amphotericin B lipid complex and 5-fluorocytosine. Early diagnosis and antifungal therapy for 6 months resulted in a favorable outcome. The detection of circulating Candida mannan in cerebrospinal fluid with a more sensitive technique combined to MRI were particularly decisive to confirm Candida infection diagnosis, allowing an appropriate antifungal therapy.

Diagnosis and Management of Central Nervous System Histoplasmosis

Two cases of Histoplasma meningitis are presented, illustrating the difficulty in diagnosis and treatment. The first case occurred in a patient with acquired immunodeficiency syndrome as a relapse of disseminated histoplasmosis and resolved after prolonged treatment and ongoing antiretroviral therapy. The second case occurred in a cardiac allograft recipient as meningitis and focal brain lesions that responded to liposomal amphotericin B, but the patient died shortly after therapy was completed. Unfortunately, there are no prospective studies addressing the diagnosis and management of patients with histoplasmosis of the central nervous system from which to provide evidence-based guidelines for care. In the absence of such data, an approach will be presented on the basis of our experience and opinions.

Neuroimaging as a Guide to Predict Outcomes for Patients with Coccidioidal Meningitis

Sixty-two patients with coccidioidal meningitis underwent neuroimaging. Magnetic resonance imaging detected neuroimaging abnormalities in 76% of patients, and computed tomography scanning detected neuroimaging abnormalities in 41.6%. The most common abnormal neuroimaging findings were hydrocephalus (51.6%), basilar meningitis (46.8%), and cerebral infarction (38.7%). Significantly elevated mortality rates were associated with hydrocephalus and hydrocephalus coexisting with infarction. Basilar meningitis did not influence outcome. Patients without neuroimaging abnormalities had a mortality rate of 7.7%.

Refractory candidal meningitis in an immunocompromised patient cured by caspofungin

Candidal meningitis is a rare infectious disease that usually leads to substantial morbidity and mortality. We present a case of candidal meningitis refractory to systemic antifungal therapy (amphotericin B and fluconazole). A 63-year-old female with lymphoblastic lymphoma and myelodysplasia with leukemia transformation developed prolonged fever and headache on the seventh day following intrathecal prophylactic chemotherapy. A lumbar puncture showed neutrophilic pleocytosis, and a cerebrospinal fluid culture yielded Candida albicans. The clinical course was complicated by brain edema, subarachnoid hemorrhage, and hydrocephalus. Parenteral therapy with amphotericin B alone or amphotericin B in combination with fluconazole or intrathecal administration of amphotericin B failed to eradicate C. albicans in the cerebrospinal fluid. After 7 days of caspofungin therapy, however, the cerebrospinal fluid became sterile and the patient gradually regained consciousness. She was discharged 1 month after completing 4 weeks of caspofungin therapy. There were two critical issues we thought to be relevant to the favorable outcome of this case. First, isolation of C. albicans was achieved by inoculating enriched liquid medium with cerebrospinal fluid. Second, there is a potential therapeutic benefit of caspofungin in treating a fungal infection of the central nervous system.

Neonatal candidiasis: analysis of epidemiology, drug susceptibility, and molecular typing of causative isolates

A prospective observational study of invasive candidiasis was conducted in the neonatal intensive care unit of Aristotle University in Hippokration Hospital between 1994 and 2000. During this period, 59 neonates developed invasive candidiasis (58 cases of candidemia and 1 case of peritonitis), resulting in an overall incidence of 1.28% that showed a decreasing trend over the study period. Eleven (18.6%) cases developed within the first week of life and the others within a mean (+/-SEM) of 13.4+/-1.7 days after birth. The three most frequent causative species were Candida albicans (65.5%), Candida parapsilosis (15.5%), and Candida tropicalis (7%). C. albicans was the predominant species between 1994 and 1998, whereas, non-albicans Candida spp., particularly C. parapsilosis, were the most frequent species during the period 1999-2000 (P<0.001). While the overall mortality due to candidemia was 29% (17 of 59 cases), mortality associated with C. albicans and C. parapsilosis was 39.5% and 11.1%, respectively (P=0.032), and that observed in the 1999-2000 period was 0% (P=0.011). Virtually all isolates were susceptible to amphotericin B, flucytosine, fluconazole, and itraconazole, and no increases in minimal inhibitory concentrations were observed during these years. With the exception of a limited cluster of cases due to genotypically identical isolates, no clonal relation of C. albicans isolates was found. Moreover, no clonal persistence of C. albicans and no decrease in antifungal drug susceptibility occurred over the 6-year study period. Non-albicans Candida spp., mostly C. parapsilosis, have emerged as important pathogens in neonatal intensive care units, with infected patients having better outcomes as compared to patients infected with C. albicans.

Central nervous system paracoccidioidomycosis: diagnosis and treatment

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis. The involvement of the central nervous system (CNS) in paracoccidioidomycosis is higher than previously thought and 2 clinical presentations have been reported, meningitis and pseudotumoral.

METHODS

Twenty medical records of patients with CNS paracoccidioidomycosis treated from 1986 to 2003 were analyzed. The follow-up ranged from 1 to 18 years (mean = 8.9 +/- 4.2).

RESULTS

Besides CNS paracoccidioidomycosis, all patients but one had the chronic systemic form and the pseudotumoral clinical presentation was the most frequent. Based on computed tomography scan findings, 4 image patterns were identified: low-density lesion with ring enhancement, lesion with calcification and ring enhancement, multiloculated low-density lesion with ring enhancement, and diffuse subarachnoid enhancement. The magnetic resonance imaging was performed in 3 patients and showed subarachnoid enhancement in 1 patient and heterogeneous lesion with ring enhancement in 2 patients. Eleven patients were submitted to medical treatment and 9 needed neurosurgical treatment; ventriculoperitoneal shunts in 4 patients, brain lesions resection in 3 patients, and partial resection of spinal cord lesions in 2 patients. Eleven patients had excellent outcome, 4 patients died, 3 are in good clinical condition with residual pulmonary dysfunction, and 1 patient was lost to follow-up.

CONCLUSIONS

The diagnosis of paracoccidioidomycosis with involvement of the CNS is difficult and clinical suspicion is a key point to achieve the correct diagnosis. Patients with early diagnosis have a favorable outcome with clinical or surgical treatment.

Multifocal sporotrichosis with meningeal involvement in a patient with AIDS

This report describes a 29-year-old man with AIDS and disseminated lymphocutaneous sporotrichosis diagnosis presenting a poor therapeutic adhesion to itraconazole therapy that later evolved to neurological impairment and death. Necropsy showed granulomatous reaction and yeast-like forms similar to Sporothrix schenckii in meninges, lymph nodes, marrow bone, skin, testicles, epididymides and pancreas. Meningeal sporotrichosis cases associated to AIDS are reviewed in brief.

[Karyotypic investigation of two cases of invasive candidiasis]

Investigation of the genetic relationship of the three Candida albicans strains isolated from each of two patients, one with C. albicans meningitis and the other with pancreatic pseudocyst (PP), by PFGE (pulsed-field gel electrophoresis), was aimed in this study. Three strains of C. albicans isolated from bloodstream, abscess and drainage fluid of the patient with PP were found to show the same karyotype, while three strains of C. albicans from cerebrospinal fluid, nasopharyngeal swab culture and stool sample of the patient with meningitis were found closely related. As a conclusion, PFGE enables to give valuable information about the probable source of transmission on individual basis in these two invasive candida infections.

[Aspergillosis of the central nervous system (clinical observation and review of literature)]

Aspergillosis of the central nervous system presents a challenge faced with the problems arising from the establishing the diagnosis, the low efficiency of treatment, and high mortality rates (about 95% as shown by some data). This paper presents a clinical case of a patient with aspergillosis-induced central nervous system lesion verified by autopsy. Possible errors in the diagnosis and treatment of the patient are analyzed. The literature data including clinical cases, etiopathogenesis, and clinical manifestations and its possible complications are presented. Groups of patients at risk for invasive aspergillosis are considered. The paper gives the data available in the foreign literature on the methods and efficiency of treatment and mortality rates in different groups of patients. The urgency of the problem in the diagnosis and treatment of cerebral aspergillosis rises with the increased number of patients with immunological disorders due to infectious diseases (HIV), social (drug addiction, alcoholism), environmental, and other factors.